 Section 35 of Principles of Geology. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recording by Dionne Johns, Salt Lake City, Utah. Principles of Geology by Charles Lyle, Chapter 16, Part 2, Mineral and Thermal Springs. Almost all springs, even those which we consider the purest, are impregnated with some foreign ingredients, which being in a state of chemical solution are so intimately blended with the water as not to affect its clearness while they render it, in general, more agreeable to our taste and more nutritious than simple rainwater. But the springs called mineral contain an unusual abundance of earthly matter in solution, and the substances with which they are impregnated correspond remarkably with those evolved in a gaseous form by volcanoes. Many of these springs are thermal. That is, their temperature is above the mean temperature of the place and they rise up through all kinds of rock, as, for example, through granite, niece, limestone or lava, but are most frequent in volcanic regions or where violent earthquakes have occurred at eras comparatively modern. The water given out by hot springs is generally more voluminous and less variable in quantity at different seasons than that proceeding from any others. In many volcanic regions, jets of steam, called by the Italians, stufas issue from fissures at a temperature high above the boiling point as in the neighborhood of Naples and in the La Pari Isles and are disengaged unceasingly for ages. Now, if such columns of steam, which are often mixed with other gasses, should be condensed before reaching the surface by coming in contact with strata filled with cold water, they may give rise to thermal and mineral springs of every degree of temperature. It is indeed by this means only and not by hydrostatic pressure that we can account for the rise of such bodies of water from great depths, nor can we hesitate to admit the adequacy of the cause if we suppose the expansion of the same elastic fluids to be sufficient to raise columns of lava to the lofty summits of volcanic mountains. Several gasses, the carbonic acid in particular, are disengaged in a free state from the soil in many districts, especially in the regions of active or extinct volcanoes. And the same are found more or less intimately combined with the waters of all mineral springs, both cold and thermal. Dr. Dobiny and other writers have remarked not only that these springs are most abundant in volcanic regions, but that when remote from them, their site usually coincides with the position of some great derangement in the strata. A fault, for example, or great fissure indicating that a channel of communication has been opened with the interior of the earth at some former period of local convulsion. It is also ascertained that at great heights in the Pyrenees and Himalaya mountains, hot springs burst out from granitic rocks and they are abundant in the Alps also. These chains having all been disturbed and dislocated at times comparatively modern as can be shown by independent geological evidence. The small area of volcanic regions may appear at first view to present an objection to these views, but not so when we include earthquakes among the effects of igneous agency. A large proportion of the land hitherto explored by geologists can be shown to have been rent or shaken by subterranean movements since the oldest tertiary strata were formed. It will also be seen in the sequel that new springs have burst out and others have had the volume of their waters augmented and their temperatures suddenly raised after earthquakes so that the description of these springs might almost with equal propriety have been given under the head of igneous causes as they are agents of a mixed nature being at once igneous and aqueous. But how, it will be asked, can the regions of volcanic heat send forth such inexhaustible supplies of water? The difficulty of solving this problem would in truth be insurmountable if we believed that all the atmospheric waters found their way into the basin of the ocean. But in boring near the shore we often meet with streams of fresh water at the depth of several hundred feet below the sea level and these probably descend in many cases far beneath the bottom of the sea when not artificially intercepted in their course. Yet how much greater may be the quantity of salt water which sinks beneath the floor of the ocean through the porous strata of which it is often composed or through fissures rent in it by earthquakes. After penetrating to a considerable depth this water may encounter a heat of sufficient intensity to convert it into vapor even under the high pressure to which it would then be subjected. This heat would probably be nearest the surface in volcanic countries and farthest from it in those districts which have been longest free from eruptions or earthquakes. It would follow from the views above explained that there must be a twofold circulation of terrestrial waters one caused by solar heat and the other by heat generated in the interior of our planet. We know that the land would be unfit for vegetation if deprived of the waters raised into the atmosphere by the sun but it is also true that mineral springs are powerful instruments in rendering the surface subservient to the support of animal and vegetable life. Their heat is said to promote the development of the aquatic tribes in many parts of the ocean and the substances which they carry up from the bowels of the earth to the habitable surface are of a nature and in a form which adapts them peculiarly for the nutrition of animals and plants as these springs derive their chief importance to the geologist from the quantity and quality of the earthy materials which like volcanoes they convey from below upwards they may properly be considered in reference to the ingredients which they hold in solution. These consist of a great variety of substances but chiefly salts with bases of lime, magnesium, aluminum and iron combined with carbonic, sulfuric and myriadic acids. Myriad of soda, silica and free carbonic acid are frequently present also springs of petroleum or liquid bitumen and of naphtha. Calcerius springs. Our first attention is naturally directed to springs which are highly charged with calcerius matter for these produce a variety of phenomena of much interest in geology. It is known that rainwater collecting carbonic acid from the atmosphere has the property of dissolving the calcerius rocks over which it flows and thus in the smallest ponds and rivulets matter is often supplied for the earthly secretions of testacea and for the growth of certain plants on which they feed but many springs hold so much carbonic acid in solution that they are enabled to dissolve a much larger quantity of calcerius matter than rainwater and when the acid is dissipated in the atmosphere the mineral ingredients are thrown down in the form of porous tuffa or of more compact travertine. Overn. Calcerius springs although most abundant in limestone districts are by no means confined to them but flow out indiscriminately from all rock formations in central France where the primary rocks are unusually destitute of limestone springs copiously charged with carbonate of lime rise up through the granite and niece. Some of these are thermal and probably derive their origin from the deep source of volcanic heat once so active in that region. One of these springs at the northern base of the hill upon which Clermont is built issues from volcanic pepperino which rests on granite. It has formed by its encrustations an elevated mound of travertine or white concretionary limestone 240 feet in length and at its termination 16 feet high and 12 wide. Another encrusting spring in the same department situated at Chalusette near Pont-Jabot rises in a nice country at the foot of a regular volcanic cone at least 20 miles from any calcerius rock. Some masses of two facious deposit produced by this spring have an olytic texture. Valley of the Elsa. If we pass from the volcanic district of France to that which skirts the Apennines in the Italian peninsula, we meet with innumerable springs which have precipitated so much calcerius matter that the whole ground in some parts of Tuscany is coated over with tufa and travertine and sounds hollow beneath the foot. In other places in the same country compact rocks are seen descending the slanting sides of hills very much in the manner of lava currents except that they are of a white color and terminate abruptly when they reach the course of a river. These consist of a calcerius precipitate from springs some of which are still flowing while others have disappeared or changed their position. Such masses are frequent on the slope of the hills which bound the valley of the Elsa one of the tributaries of the Arno which flows near Kala through a valley several hundred feet deep shaped out of a lacustrine formation containing fossil shells of existing species. I observed here that the travertine was unconformable to the lacustrine beds its inclination according with the slope of the sides of the valley one of the finest examples which I saw was at the Molino della Caldea near Kola the Sena and several other small rivulets which feed the Elsa have the property of encrusting wood and herbs with calceria stone. In the bed of the Elsa itself aquatic plants such as Carrier which absorb large quantities of carbonate of lime are very abundant. Baths of San Vignon those persons who have merely seen the action of petrifying waters in England will not easily form an adequate conception of the scale on which the same process is exhibited in those regions which lie nearer to the active centers of volcanic disturbance. One of the most striking examples of the rapid precipitation of carbonate of lime from thermal waters occurs in the hill of San Vignon in Tuscany at a short distance from Radicofani and only a few hundred yards from the high road between Siena and Rome. The spring issues from near the summit of a rocky hill about 100 feet in height. The top of the hill stretches in a gently inclined platform to the foot of Mount Amiata, a lofty eminence which consists in great part of volcanic products. The fundamental rock from which the spring issues is a black slate with serpentine belonging to the older aponyne formation. The water is hot, has a strong taste and when in not very small quantity is of a bright green color. So rapid is the deposition near the source that in the bottom of a conduit pipe for carrying off the water to the baths and which is inclined at an angle of 30 degrees half a foot of solid traverton is formed every year. A more compact rock is produced where the water flows slowly and the precipitation in winter when there is least evaporation is said to be more solid but less in quantity by one fourth than in summer. The rock is generally white. Some parts of it are compact and ring to the hammer. Others are cellular and with such cavities as are seen in the carrious part of bone or the salacious millstone of the Paris basin. A portion of it also below the village of Saint-Vignon consists of incrustations of long vegetable tubes and may be called tufa. Sometimes the traverton assumes precisely the bot-trioidal and mammillary forms come into similar deposits in avern of a much older date and like them it often scales off in thin, slightly undulating layers. A large mass of traverton descends the hill from the point where the spring issues and reaches to the distance of about half a mile east of Saint-Vignon. The beds take the slope of the hill at an angle of six degrees and the planes of stratification are perfectly parallel. One stratum composed of many layers is of a compact nature and 15 feet thick. It serves as an excellent building stone and a mass of 15 feet in length was in 1828 cut out for the new bridge over the Orsia. Another branch of it descends to the west for 250 feet in length of varying thickness but sometimes 200 feet deep. It is then cut off by the small river Orsia as some glaciers in Switzerland descend into a valley till their progress is suddenly arrested by a transverse stream of water. The abrupt termination of the mass of rock at the river where its thickness is undiminished clearly shows that it would proceed much farther if not arrested by the stream over which it impends slightly but it cannot encroach upon the channel of the Orsia being constantly undermined so that its solid fragments are seen strewed amongst the alluvial gravel. However enormous, therefore the mass of solid rock may appear which has been given out by this single spring we may feel assured that it is insignificant in volume when compared to that which has been carried to the sea since the time when it began to flow. What may have been the length of that period of time we have no data for conjecturing in quarrying the Travertin Roman tiles have been sometimes found at the depth of five or six feet baths of San Filippo. On another hill, not many miles from that last mentioned and also connected with Mount Amiata the summit of which is about three miles distant are the celebrated baths of San Filippo. The Subjacent Rocks consist of alternations of black slate limestone and serpentine. There are three warm springs containing carbonate and sulfate of lime and sulfate of Magnesia. The water which supplies the baths falls into a pond where it has been known to deposit a solid mass 30 feet thick in about 20 years. A manufacturer of medallions in Basso Relivo is carried on at these baths. They are conducted by canals into several pits in which it deposits Travertin and crystals of sulfate of lime. After being thus freed from its grosser parts it is conveyed by a tube to the summit of a small chamber and made to fall through a space of 10 or 12 feet. The current is broken in its descent by numerous crossed sticks which the spray is dispersed around upon certain moles which are rubbed lightly over with a solution of soap and a deposition of solid matter like marble is the result yielding a beautiful cast of the figures formed in the mold. The geologist may derive from these experiments considerable light in regard to the high slope at which some semi-crystalline precipitations can be formed. For some of the molds are disposed almost perpendicularly yet the deposition is nearly equal in all parts. A hard stratum of stone about a foot in thickness is obtained from the waters of San Filippo in four months and as the springs are powerful in the quantity given out we are at no loss to comprehend the magnitude of the mass which descends the hill which is a mile and a quarter in length and the third of a mile in breadth in some places attaining a thickness of 250 feet at least. To what length it might have reached it is impossible to conjecture as it is cut off like the Traverton of San Vignone by a small stream where it terminates abruptly the remainder of the matter held in solution is carried on probably to the sea spheroidal structure in Traverton but what renders this recent limestone of peculiar interest to the geologist is the spheroidal form which it assumes analogous to that of the cascade of Tivoli afterwards to be described. The lamination of some of the concentric masses is so minute that 60 may be counted in the thickness of an inch yet notwithstanding these marks of gradual and successive deposition sections are sometimes exhibited of what might seem to be perfect spheres this tendency to a mammillary and globular structure arises from the facility with which the calcerius matter is precipitated in nearly equal quantities on all sides of any fragment of shell or wood or any inequality of the surface over which the mineral water flows the form of the nucleus being readily transmitted through any number of successive envelopes but these masses can never be perfect spheres although they often appear such when a transverse section is made in any line, not in the direction of the point of attachment. There are indeed occasionally seen small olytic and pysolytic grains of which the form is globular for the nucleus having been for a time in motion in the water has received fresh accessions of matter on all sides in the same manner I have seen on the vertical walls of large steam boilers the heads of nails or rivets covered by a series of enveloping crusts of calcerius matter usually sulfate of lime so that a concretionary nodule is formed in a nearly globular shape when increased to a mass several inches in diameter. In these as in many travertins there is often a combination of the concentric and radiated structure Campania de Roma the country around Rome like many parts of the Tuscan states already referred to has been at some former period as volcanic eruptions and the springs are still copiously impregnated with lime, carbonic acid and sulfur-edded hydrogen. A hot spring was discovered about 1827 near Civita Vecchia by Signor Riccioli which deposits alternate beds of a yellowish travertin and a white granular rock not distinguishable in hand specimens either in grain, color or composition from statuary marble. There is a passage between this and ordinary travertin. The mass accumulated near the spring is in some places about six feet thick. End of chapter 16 part two. Chapter 36 of Principle of Geology This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer please visit LibriVox.org Recording by Emanuella Principle of Geology by Charles Lille whether species have a real existence in nature continued phenomena of hybrids, hunter's opinions Muse not strictly intermediates between parent species Hybrid plants Experiments of Curr-Reuter and Bigman Vegetable hybrids prolific throughout several generations Why rare in a wild state Duke-Andal on hybrid plants the phenomena of hybrids confirmed the distinctness of species Theory of degradation in the intelligence of animals as indicated by the facial angle Doctrine that certain organs of the fetus Emanuella assume the form of fish, reptile and bird Recapitulation Phenomena of hybrids We have yet to consider another class of phenomena those relating to the production of hybrids which have been regarded in a very different light with reference to their bearing to the question of the permanent distinctness of species Some naturalists considering them as affording the strongest of all proofs in favor of the reality of species Others, on the contrary, appealing to them as countenancing the opposite doctrine that all the varieties of organization related in the animal and vegetable kingdoms may have been propagated from a small number of original types In regard to the mammifers and birds it is found that no sexual union will take place between races which are removed from each other in the habits and organization and it is only in species that are very nearly allied that such unions produce offspring It may be laid down as a general rule admitting a very few exceptions among quadruplets that the hybrid progeny is sterile and there seem to be no well authenticated examples of the continuance of the male race beyond one generation The principal number of observations and experiments relate to the mix of springs of the horse and the ass and in this case it is well established that the humule can generate and the humule produce Such cases occur in Spain and Italy and much more frequently in the West Indies and New Holland But these mules have never bred in cold climates seldom in warm regions and still more rarely in temperate countries The hybrid offspring of the she-ass and the stallion, the hinnosh of Aristotle and the hinnos of Guigny differs from the mule or the offsprings of the ass and mare In both cases says Buffon these animals retain more of the dam than of the sire, not only in the magnitude but in the feature of the body whereas in the form of the head, limbs and tail there is a resemblance to the sire The same naturalist infers from various experiments respecting crossbreeds between the he goat and the you the dog and she wolf, the goldfinch and canary bird that the mare transmits his sex to the greatest number and that the preponderance of males over females exceeds death which prevails where the parents are of the same species Hunter's Opinion The celebrated John Hunter has observed that the true distinction of species must ultimately be gathered from the incapacity of propagating with each other and producing offspring capable of again continuing itself He was unwilling, however to admit that the horse and the ass were of the same species because some rare instances had been adduced of the breeding of mews although he maintained that the wolf, the dog and the jackal were all of one species because he had found, by two experiments that the dog would breed both with the wolf and the jackal and that the mule in each case would breed again with the dog In these cases, however, it may be observed that there was always one parent at least of pure breeds and no proof was obtained that the true hybrid race could be perpetuated a fact of which, I believe, no examples are yet recorded either in regard to mixtures of the horse and the ass or any other of the mammalia Should the fact be hereafter ascertained that two mews can propagate their kind we must still inquire whether the offspring may not be regarded in the light of a monstrous birth proceeding from some accidental cause or, rather, to speak more philosophically from some general law not yet understood but which may not be permitted permanently to interfere with those laws of generation by which species may, in general be prevented from becoming blended If, for example, we discovered that the progeny of a mule race degenerated greatly in the first generation in force, sagacity or any attribute necessary for its preservation in a state of nature we might infer that, like a monster it is a mere temporary and fortuitous variety nor does it seem probable that the greater number of such monsters could ever occur unless obtained by art For, in hunter's experiments stratagem or force was, in most instances employed to bring about the irregular connection Mews not strictly intermediate between the parent species it seems rarely to happen that the mule offspring is truly intermediating character between the two parents Thus, Hunter mentions that in his experiments one of the hybrid poops resembled the wolf much more than the rest of the litter and we are informed by Wigman that, in a litter lately obtained in the Royal Menagerie at Berlin, from a white pointer and a she-wolf two of the cubs resembled the common wolf dog but the third was like a pointer with a hanging ears There is, undoubtedly a very close analogy between this phenomena and those presented by the intermixture of distinct races of the same species both in the inferior animals and in men Dr. Pritchard, in his Physical History of Mankind cites examples where the peculiarities of the parents have been transmitted very equally to the offspring as well children entirely white or perfectly black have sprung from the union of the European and the Negro Sometimes the color or other peculiarities of one parent after having failed to show themselves in the immediate progeny reappear in a subsequent generation as where a white child is born of two black parents the grandfather having been a white The same author judiciously observes that if different species mix at their breed and hybrid races were often propagated the animal world would soon present a scene of confusion its tribes would be everywhere blended together and we should perhaps find more hybrid creatures than genuine and uncorrupted races Hybrid Plants Kill Reuters Experiments The history of the Vegetable Kingdom has been thought to afford more decisive evidence in favour of the theory of the formation of new and permanent species from hybrid stocks The first accurate experiments in illustration of this curious subject appear to have been made by Col. Reuter who obtain a hybrid from two species of Tobacco Nicoziana Rustica and Nicoziana Paniculata which differ greatly in the shape of their leaves the color of the corolla and the height of the stem The stigma of a plant of Nicoziana Rustica was impregnated with the pollen of a plant of Nicoziana Paniculata The seed ripened and produced a hybrid which was intermediate between the two parents and which, like all the hybrids had imperfect stamings He afterwards impregnated this hybrid with the pollen of Nicoziana Paniculata and obtained plants which much more resembled the last This he continued through several generations until, by super severance he actually changed the Nicoziana Rustica into the Nicoziana Paniculata The plan of impregnation adopted was the cutting off of the enters of the plant intended for fructification before they had shed pollen and then laying on foreign pollen upon the stigma Wickman's experiments The same experiment has since been repeated with success by Wickman who found that he could bring back the hybrids to the exact lightness of their parent by crossing them a sufficient number of times The blending of the characters of the parent's stocks and many other of Wickman's experiments was complete The color and shape of the leaves and flowers and even the scent being intermediate as in the offspring of the two species of Berbascum an intermarriage also between the common onion and the leek Allium Cepa and Allium Porrum gave a mule plant which, in the character of its leaves and flowers approached it most nearly to the garden onion but had the elongated bulbous root and smell of the leek The same botanist remarks that vegetable hybrids were not strictly intermediate more frequently approached the female than the male parent's species but they never exhibit characters foreign to both A recross with one of the original stocks generally causes the mule plant to revert towards that stock but it is not always the case the offspring sometimes continuing to exhibit the character of a full hybrid In general, the success attended the production and perpetuity of hybrids among plants depends as in the animal kingdom on the degree of proximity between the species intermarried if their organization be very remote impregnation never takes place if somewhat less distant seeds are formed but always imperfect and sterile the next degree of relationship yields hybrid seedings but these are barren and it is only when the parent's species are very nearly allied that the hybrid race may be perpetuated for several generations even in this case the best authenticated examples seem confined to the crossing of hybrids with the individuals of pure breed in none of the experiments most accurately detailed does it appear that both the parents were mules Wigman diversified as much as possible his mode of bringing about these irregular unions among plants he often saw with parallel rows near to each other of the species from which he desired to breed and instead of mutilating up till Coroiter's fashion the plants of one of the parent's stocks he merely washed the pollen off their anthers the branches of the plants in each row were then gently bent towards each other and intertwined so that the wind and numerous insects as they passed from the flowers of one to those of the other species carried the pollen and produced facundation Predictable hybrids were rare in a while state the same observer saw a good simplification of the manner in which hybrids may be formed in a state of nature some wall flowers and pinks had been growing in a garden in a dry sunny situation and their stigmas had been ripened so as to be moist and to absorb pollen with avidity although the anthers were not yet developed these stigmas became impregnated by pollen blown from some other addition plants of the same species but had they been of different species and not too remote in the organization mule races must have resulted when indeed we consider how busily some insects have been shown to be engaged in conveying anther dust from flower to flower especially bees flower-eating beetles and the like it seems the most enigmatic problem how it can happen that promiscuous alliances between distinct species are not perpetually curing how continually do we observe the bees diligently employed in collecting the red and yellow powder by which the stamens of flowers are covered loading it on their hind legs and carrying it to their hive for the purpose of feeding their young in thus providing for their own progeny these insects assist materially the process of fortification few persons need to be reminded that the stamens in certain plants grow on different blossoms from the pistils and unless the summit of the pistil be touched with the fertilizing dust the fruit does not swell nor the seed arrive at maturity it is by the help of bees chiefly that the development of the fruit of many such species is secured the powder which they have collected from the stamens being unconsciously left by them in visiting the pistils how often during the heat of a summer's day do we see the maze of the issues plants such as the U3 standing separate from the females and sending off into the air upon the slightest breath of wind clouds of Bojan pollen that the Zephyr should so rally intervene so fecundate the plants of one species with the enter dust of others seems almost to realize the converse of the miracle believed by the creedless herdsmen of the Lusitanian mares ore omnes verse in Zephyrum stant rupibus altis acceptan que leves auras et sepesi neullis conugis vento gravide mirabile dictu but in the first place it appears that there is a natural version in plant as well as in animals to regular sexual unions and in most of the successful experiments in the animal and vegetable world some violence has been used in order to procure impregnation the stigma imbibes slowly and reluctantly the granules of the pollen of another species even when it is abundantly covered with it and if it happened that during this period ever so slightly quantity of the enter dust of its own species allied upon it this is instantly absorbed and the effect of the foreign pollen destroyed besides, it doesn't often happen that the male and female organs of rectification in different species arrived at state of maturity at precisely the same time even where such synchronisms does prevail so that a cross impregnation is affected the chances are very numerous against the establishment of a hybrid race if we consider the vegetable kingdom generally it must be recollected that even of the seeds which are well ripen a great part are either eaten by insects birds and other animals or decay for want of room and opportunity to germinate unearthly plants are the first which are cut off by causes prejudicial to the species being usually stifled by more vigorous individuals of their own kind if, therefore, the relative fecunity or ardiness of hybrids being the least degree inferior they cannot maintain their footing for many generations even if they were ever produced beyond one generation in a wise state in the universal struggle for resistance the right of the strongest eventually prevails and the strength and durability of race depend mainly on its prolificness in which hybrids are acknowledged to be deficient Centauri hybrida a plant which never bears seed and is supposed to be produced by the fragmented mixture of two well known species of Centauria grows wild upon a hill near Turin Ranunculus Lacerus also sterile has been produced accidentally at Grenoble and near Paris by the union of two Ranunculi but this occurred in gardens Mr. Herbert's experiments Mr. Herbert in one of his ingenious papers showed the plants and devils to account for their non-occurrence in a state of nature from the circumstance that all the combinations that were likely to occur have already been made many centuries ago and have formed the value species of botanists but in our gardens he says whenever species having a certain degree of affinity to each other are transported from different countries in contact they give rise to hybrid species but we have no data as yet to warrant the conclusion that a single permanent hybrid race has ever been formed even in gardens by the intermarriage of two allied species brought from distant habitations until some fact of this kind is fairly established and the new species capable of perpetuating itself in a state of perfect independence no doubt it seems reasonable to call in question entirely this hypothetical source of new species that varieties do sometimes spring up from crossbreeds in a natural way can hardly be doubted but they probably die out even more rapidly than races propagated by graphs or layers Opinion of Ducandol Ducandol whose opinion on a philosophical question of this kind observes the greatest attention has observed in his essay on botanical geography that the varieties of plants range themselves under two general heads those produced by external circumstances and those formed by hybridity after reducing various arguments to show that neither of these causes can explain the permanent diversity of plants indigenous in different regions as he says in regard to the crossing of races I can perfectly comprehend without altogether sharing the opinion that where many species of the same genera occur near together hybrid species may be formed and I am aware that the great number of species of certain genera which are found in particular region may be explained in this manner but I am unable to conceive how anyone can regard the same explanation as applicable to species which live naturally at great distances if the three largest for example now known in the world lived in the same localities I might then believe that one of them was the produce of the crossing of the two others but I never could admit that the Siberian species has been produced by the crossing of those of Europe and America I see then that there exist in organized beings permanent differences which cannot be referred to any one of the actual causes of variation and these differences are what constitutes species reality of species confirmed by the phenomena of hybrids the most decisive arguments perhaps amongst many others against the probability of the derivation of permanent species from crossbreeds are to be drawn from the fact alluded to by Duke and all of species having a close affinity to each other occurring in distinct botanical provinces or countries inhabited by groups of distinct species of indigenous plants for in this case naturalists who are not prepared to go the whole length of the transmutationists are under the necessity of admitting that in some cases species which approach very near to each other in their characters were so created from their origin an admission fatal to the idea of its being a general law of nature that a few original types only should be formed and that all intermediate races should spring from the intermixture of those stocks this notion indeed is holy at various with all that we know of hybrid generation for the phenomena entitled last to affirm that had the types being at first somewhat d'instinct no crossbreeds would ever have been produced much less those prolific races which we now recognize as d'instinct species in regard moreover to the permanent propagation of hybrid races among animals insuperable difficulties present themselves when we endeavour to conceive the blending together of the different d'instincts and properties of two species so as to ensure that preservation of the intermediates race the common mule when obtained by human art may be protected by the power of man but in a wild state it would not have precisely the same ones either as yours or the s and if in consequence of some difference of this kind it strayed from the herd it would soon be hunted down by beasts for prey and destroyed if we take some genus of insects such as the bee we find that each of the numerous species have some difference in its habits its mode of collecting honey or constructing its dwelling or providing for its young and other particulars in the case of the common hive bee the workers are described by Kirby and Spence as being endowed with no less than 30 d'instinct instincts so also we find that amongst a most numerous class of spiders there are nearly as many different modes of spinning their webs as there are species when we recollect how complicated are the relations of these instincts with co-existing species both of the animals and vegetable kingdoms it is scarcely possible to imagine that the bastard rays could spring from the you know two of these species and retain just so much of the qualities of each parent's stock as to preserve its ground in spite of the dangers which surround it we might also ask if a few generic types alone have been created by long insects and the intermediate species have proceeded from hybridity where are those original types combining as they ought to do the elements of all the instincts which have made their appearance in the numerous derivative races so also regard to animals of all classes and of plants if species are in general of hybrid origin where are the stocks which combining themselves the habits, properties of which all the intervening species ought to afford us mere modifications recapitulation of the arguments from hybrids I shall now conclude this subject by summing up in a few words the result to which I have been led by the consideration of the phenomena of hybrids it appears that the evasion of individuals of the instinct species to the sexual union is common to animals and plants and it is only when the species approach near to each other in their organization and habits that any offspring are produced from their connection muses are of extremely rare occurrence in a state of nature and known samples are yet known of their having procreated in a wild state but it has been proved that hybrids are not universally sterile yet in the parent stocks have a near affinity to each other although the continuation of the mixed race for several generations appears there to have been obtained only by crossing the hybrids with individuals of pure species an experiment which by no means bears out the hypothesis that a true hybrid race could ever be permanently established hence we may infer that the sexual intercourse is in general a good test of the distinctness of original stocks or of a species and the procreation of hybrids is a proof of the near affinity of species perhaps hereafter the number of generations for which hybrids may be continued before the race dies out for it seems usually to generate rapidly may afford the zoologist and botanist an experimental test of the difference in the degree of affinity of allied species I may also remark that if it could have been shown that a single permanent species had ever been produced by hybridity of which there is no satisfactory proof it might certainly have lent some countenance to the notions of the ancients respecting the gradual deterioration of created things but none whatsoever to landmarks theory of their progressive perfectibility for observations have it there to show that there is a tendency in mule animals and plants to degenerate in organization it was before remarked that the theory of progressive development arose partly from an attempt to ingraft the doctrines of the transmutationists upon one of the most popular generalization of geology but we have seen in the ninth chapter that the modern researches of geologists have broken at many points the chain of evidence one supposed to exist in favor of the doctrine that at each successive period in the earth history animals and plants of a higher grade or more complex organization have been created the recent origin of man and the absence of all science of any rational being holding an analogous relation to former states of the animate world affords one and perhaps in the present state of science the only argument of much weight in support of the hypothesis of a progressive scheme but none whatsoever in favor of the fancy devolution of one species out of another theory of the gradation of intellect as shown by the fashion angle when the celebrated anatomist camper first attempted to estimate the degrees of sagacity of different animals and of the races of man by the measurement of the fashion angle some speculators were bold enough to affirm that certain simiae or apes deferred as little from the most savage races of man as those do from the human race in general and that a scale might be traced from apes with foreheads with lanus loam to the african variety of the human species and from that to the european the fashion angle was measured by drawing a line from the prominent center of the forehead to the most advanced part and observing the angle which it made with the horizontal line and it was affirmed that there was a regular series of such angles from birth to the mamalia the gradation from the dog to the monkey was said to be perfect and from that again to man one of the ape tribe has a fashion angle of 42 degrees and another which approximated the nearest to man in the future an angle of 50 degrees today succeeds longo sed proximus intervallo the head of the african negro which as well as that of the kaumuk forms an angle of 70 degrees while that of the european contains 80 degrees the roman painters preferred the angle of 95 degrees and the character of beauty and sublimity so striking in some works of fritian sculpture has in the head of the apollo and in the medusa of sisocles is given by an angle which amounts to 100 degrees a great number of valuable facts and curious analogies in comparative anatomy were brought to light during the investigations which were made by kamper, john hunter and others to illustrate the scale of the organization and their facts and generalizations must not be confounded with the fanciful systems which white and others deduce from them that there is some connection between an elevated and capacious forehead in certain races of man and the large development of the intellectual faculties seems highly probable and that a low facial angle is frequently interpanned with inferiority of mental powers is certain but the attempt to trace a gradual scale of intelligence through the different species of animals accompanying the modifications of the form of the skull is a mere visionary speculation it has been found necessary to exaggerate the sagacity of the ape tribe at the expense of the dog and strange contradictions that deduce from the structure of the elephant some anatomists being disposed to deny the quadrupedity intelligence which he really possesses because they found that the volume of his brain was small in comparison to that of the other mammalia while others were inclined to magnify extravagantly the superiority of his intellect because the vertical height of his skull is so great when compared to its horizontal length different races of men are all or one species it would be irrelevant to our subject if we were to enter into a further discussion on these topics because even if a graduated scale of organization and intelligence could have been established it would prove nothing in favor of a tendency in each species to attain a higher state of perfection I refer the reader to the writings of Blumenbach Pritchard Lawrence and more recently Latham for convincing proof that the variety of form color and organization of different races of men are perfectly consistent with the general received opinion that all the individuals of the species have originated from a single pair and while they exhibit in men as many diversities of a physiological nature as appear in any other species they confirm also the opinion of the slight deviation from a common standard of which species are capable the power of existing and multiplying every latitude and in every variety of situation and climate which has enabled the great human family to extend itself over the habitable globe is partly says Lawrence the result of physical constitution and partly of the mental prerogative of men if he did not possess the most enduring and flexible corporeal frame his arts would not enable him to be the inhabitant of the old climates and to brave the extremes of heat and cold and the other destructive influences of local situation yet notwithstanding the flexibility of bodily frame we find no signs of indefinite departure from a common standard and the intermarriages individuals of the most remote varieties are not less fruitful than between those of the same tribe Teedman on the brain of the fetus in vertebrated animals there is yet another department of anatomical discovery to which I must allude because it has appeared to some persons to afford a distant analogy at least to that progressive development by which some of the inferior species may have been gradually perfected into those of more complex organization Teedman found and his discoveries have been most fully confirmed and elucidated by Serre that the brain of the fetus in the highest class of vertebrated animals assumes in succession forms bearing a certain degree of resemblance to those which belong to fishes, reptiles and birds before it acquires the additions and modifications which are peculiar to the mammifera of the tribe so that in the passage from the embryo to the perfect mammifera there is a typical representation it is said of all those transformations which the primitive species are supposed to have undergone during a long series of generations between the present period and the remotest geological era if you examine the brain of the mammalia says Serre at an early stage of uterine life you perceive the cerebral hemispheres consolidated as in fish in two vesicles isolated one from the other at a later period you see them affect the configuration of the cerebral hemispheres of reptiles still later again they present you with the forms of those of birds finally they acquire at the era of birth and sometimes later the permanent forms which the adult mammalia present the cerebral hemispheres then arrive at the state which we observe in the higher animals only by a series of successive metamorphoses if we reduce the whole of these evolutions to four periods we shall see that the first are born the cerebral lobes of the fishes or more genuously in all classes the second period will give us the organization of reptiles the third the brain of birds and the fourth the complex hemispheres of mammalia if we could develop the different parts of the brain in the inferior classes we should make as a session a reptile out of a fish a bird out of a reptile and the mammiferal squadruped out of a bird if on the contrary we could starve this organ in the mammalia we might reduce it succively to the condition of the brain of the three inferior classes nature often presents us with this last phenomenon in monsters but never exhibits the first among the various deformities which organized being may experience they never pass the limits of their own classes to put on the forms of the class above them never does a fish elevate itself so as to assume the form of the brain of a reptile nor does the latter even attain deaths of birds nor the bird death of the mammiferal it may happen that a monster may have two heads but the conformation of the brain always remains circumscribed narrowly within the limits of its class Dr. Clark of Cambridge in a memoir on fatal development 1845 has shown that the current labors of Valentin Rakhe and Bischoff disprove the reality of the supposed anatomical analogy between the embryo condition of certain organs in the higher orders and the perfect structure of the same organs in animals of an inferior class the hearts and brains, for example of birds and mammals do not pass through forms which are permanent in fishes and reptiles there is only just so much resemblance as may points to a unity of plan running through the organization of the whole series of vertebrate animals but which lends no support whatever to the notion of a gradual transportation of one species into another list of all of the passage in the course of many generations from an animal of a more simple to one of a more complex structure recapitulation for the reasons therefore detailed in this and the two preceding chapters we may draw the following inferences in regard to the reality of species in nature first that there is a capability in all species to accommodate themselves to a certain extent to a change of external circumstances this extent varying greatly according to the species secondly when the change of situation which they can endure is great it is usually attended by some modifications of the form, color, size, structure or other particulars but the mutations thus super inducted are governed by constant lows and the capability of sovaring forms part of the permanent specific character thirdly some acquired peculiarities of form, structure and instinct are transmissible to the offspring but this consist of such qualities and attributes only as are intimately related to the natural ones and propensities of the species fourthly the entire variation from the original type which any given kind of change can produce may usually be affected in a brief period of time after which no further deviation can be obtained by continuing to alter the circumstances though ever so gradually indefinite divergence either in the way of improvement or deterioration being prevented and the least possible excess beyond the defined limits being fatal to the existence of the individual fifthly the intermixture of distinct species is guarded against by the version of the individuals composing them of the intersexual union or by the sterility of the male offspring it does not appear that true hybrid races have ever been perpetuated for several generations even by the assistance of men for the cases usually cited relate to the crossing of mules with individuals of pure species and not to the intermixture of hybrid with hybrid sixthly from the above considerations it appears that species have a real existence in nature and that each was endowed at the time of its creation with the attributes and organization by which it is now distinguished and of chapter 36 recording by Emanuela chapter 17 part 1 of principle of geology this is a LibriVox recording all LibriVox recordings are in the public domain for more information or to volunteer please visit LibriVox.org recording by Emanuela principle of geology by Charles Lyle chapter 17 part 1 reproductive effects of rivers lake deltas growth of the delta of the upper Rhine in the lake of Geneva computation of the age of deltas recent deposits in lake superior deltas of island seas coast of the pole artificial embankments of the pole and edige delta of the pole and other rivers entering the adiatric rapid conversion of that gulf into land mineral characters of the new deposits marine delta of the Rhine various proof of its increase stony nature of its deposits coast of Asia Minor delta of the Nile deltas in lakes have already spoken in the 14th chapter of the action of running water and of the denuding power of rivers but we can only form a just conception of the excavating and removing force exerted by such bodies of water when we have the advantage of examining the reproductive effects of the same agents in other words of beholding in a palpable form the aggregate amount of matter which they have thrown down at certain points in the lalluvial plains or in the basin of lakes and seas yet it will appear to be considered the action of currents that the growth of delta are for the very inadequate standard by which to measure the entire current power of running water since a considerable portion of Luviatil sediment is swept far out to sea deltas may be divided into first those which are formed in lakes secondly those in island seas where the tides are almost imperceptible and thirdly those on the borders of the ocean the most characteristic distinction between the lacostrine and marine deltas consists in the nature of the organic remains which become embedded in their deposits 4. in the case of a lake it is obvious that this must consist exclusively of such general venomous as inhabits the land or the waters of a river or a lake whereas in the other case there will be an atmosphere and most frequently an predominance of animals which inhabits salt water in regard however to the distribution of inorganic matter the deposits of lakes and seas are formed under very analogous circumstances lake of Geneva lakes exemplify the first reproductive operations in which rivers are engaged when they conveyed the treatise of rocks and the even jets of mineral springs for mountainous regions the accession of new land at the mouth of the Rhone at the upper end of the lake of Geneva or the Lehman lake presents us with an example of a considerable thickness of strata which have accumulated since the historical era this sheet of water is about 37 miles long and its breadth is from 2 to 8 miles the shape of the bottom is very regular the depth having been found by lake measurement to vary from 20 to 160 phalons the Rhone where it empties at the upper end is turbid and discolored but its waters where its issues at the town of Geneva are beautifully clear and transparent a nation town called Port-Balais Portus-Balaisie of the Romans once situated at the water's edge at the upper end is now more than a mile and a half England these intervening alluvial tract having been acquired in about 8 centuries the reminder of the delta consists of a flat alluvial plane about 5 or 6 miles in length composed of sand and mud a little raised above the level of the river and full of marshes Sierra de la Beach found, after numerous soundings in all parts of the lake that there was a pretty uniform depth of from 120 to 160 phalons throughout the central region and on approaching the delta the shallowing of the bottom began to be very sensible at a distance of about a mile and 3 quarters from the mouth of the Rhone from a line drawn from San Guingulf to the Vey gives a mean depth of somewhat less than 600 feet and from that part of the Rhone the Fruviatil mud is always found along the bottom we may state therefore that the new strata annually produced are thrown down upon a slope about 2 miles in length so that, notwithstanding the great depths of the lake the new deposits are inclined at an angle that the deep of the beds would be termed in ordinary geological language horizontal the strata probably consists of alternation of finer and coarser particles for, during the hotter months from April to August when the slows melt the volume and velocity of the river are greatest and large quantities of sand, mud vegetable matter and driftwood are introduced but during the rest of the year the influx is comparatively feeble so much so that the whole lake according to Shosu stands 6 feet lower if then we could obtain a section of the accumulation formed in the last 8 centuries we should see a great series of strata probably from 600 to 900 feet thick the supposed original depth of the head of the lake and nearly 2 miles in length inclined at a very slight angle in the meantime a great number of small deltas are growing around the borders of the lake at the mouths of rapid torrent which pour in large masses of sand and pebbles the body of water in this torrent is too small to enable them to spread out the transported matter over so extensive an area as the room does thus for example there is a depth of 80 atoms within half a mile of the shore immediately opposite the great torrent which enters east of Ripo so that the deep of the strata is that minor delta must be about far times as great as those deposit by the main river at the upper extremity of the lake chronological computations of the age of deltas the capacity of this basin being now a certain it would be an interesting subject of enquiry to determine in what number of years the limon lake would be converted into a dry land it would not be very difficult to obtain the elements for such calculation so as to approximate at least to the quantity of time required for the accompaniment to the better result the number of cubic feet of water annually discharged by the river into the lake being estimated experiments might be made in the winter and summer months to determine the proportion of matter held in suspension or in chemical solution by the room it would be also necessary to allow for the heavier matter drift along at the bottom which might be estimated on hydrostatical principle when the average size of the gravel and the volume and velocity of the stream at different seasons supposing all these observations to have been made it would be more easy to calculate the future than the former progress of the delta because it would be a laborious task to ascertain with any degree of precision the original depth an extent of that part of the lake which is already filled up even if this information were actually obtained by borings it would only be able to approximate within a certain number of centuries to the time when the world began to form its present delta but it would not give us the date of the origin of the liman lake in its present form because the river may have flowed into it for a thousand of years without importing any sediment whatever such would have been the case if the waters had first passed through a chain of upper lakes and that this was actually the fact seems indicated by the course of the roam between Martigny and Lake of Geneva and still more decidedly by the channels of many of its principal feeders if we ascend for example the valley through which the drums flows we find that it consists of a section of basins one above the other in each of which there is a wide expanse of flat alluvial lands from the next basin by a rocky gorge once perhaps the barrier of a lake the river seems to have filled these lakes one after the other and to have partially cut through the barriers some of which it is still gradually eroding to a greater depth before therefore we can pretend even to azar the conjecture as to the era at which the principal delta of Lake Liman or any other delta commenced we must be throughout the acquainted with geographical features and geological history of the whole system of higher valleys which communicate with the mainstream and all the changes which they have undergone since the last series of convulsions which agitated and altered the face of the country Lake Superior Lake Superior is the largest body of fresh water in the world being above 1,700 geographical miles in circumference when we follow the sinuosities of its coast and its length on a curved line drawn through its center being more than 400 and in extreme breadth above 150 geographical miles its surface is nearly as large as the whole of England its average depth varies from 80 to 150 fathoms but according to captain Bayfield there is a reason to think that its greatest depth would not be overrated at 200 fathoms so that its bottom is, in some parts nearly 600 feet below the level of the Atlantic its surface being about as much above it there are appearances in different parts of this as of the other Kaladian lakes leading us to the infer where its water formerly occupied a higher level than they reached at the present for a considerable distance from the present shores parallel lines of rolled stones and shells are seen rising one above the other like the seats of an amphitheater these ancient lines of shingle are exactly similar to the present beaches in most bays and they often attain an elevation of 40 or 50 feet above the present level as the heaviest case of wind do not raise the waters more than 3 or 4 feet the elevated beaches have by some been referred to the subsidence of the lake at former periods in consequence of the wearing down of its barrier by others to the appraising of the shores by earthquakes like those which have produced similar phenomena on the coast of Chile these which discharged their waters into lakes superior are several hundred in number without reckoning those of smaller size and the quantity of water supplied by them is many times greater than that discharged the falls of San Mary the only outlet the evaporation therefore is very great and such as may be expected from so vast an extent of surface on the northern side of the primary mountains the rivers are sweeping many large boulders with smaller graver and sand chiefly composed of granitic and trapped rocks there are also currents in the lake in various directions caused by the continued prevalence of strong winds and to their influence we may attribute the diffusion of finer mud far and wide over great areas for by numerous soundings made during captain survey it was a certain that the bottom consists generally of a very adhesive clay containing shells of the species that present existing in the lake when exposed to the air this clay immediately becomes ingerated in so great a degree as to require a smart blow to break it it effervesces lightly with diluted nitric acid and is of different colors in different parts of the lake in one district blue in another red and in a third white hardening into a substance resembling pipe clay from these statements the geologists will not fail to remark how closely these recent acoustic formations in America resemble the tertiary argileus and calcareous moors of acoustic origin in central France in both cases many of the general shells most abundant as limnayan are the same and in regard to other classes of organic remains there must be the closest analogy as I shall endeavour more fully to explain when speaking of the embedding of plants and animals in recent deposits having thus briefly considered some of the clacustin deltas now in progress we may next turn our attention to those of inland seas course of the Pau the Pau affords an instructive example of the manner in which a great river bears down to the sea the matter poured into it by a multitude of tributaries descending from lofty chains of mountains the changes gradually affected in the great plain of Dortholedery since the time of the Roman Republic are considerable extensive lakes and marshes are readily filled up as doors near Placencia, Parma and Cremona and many have been drained naturally by the deepening of the beds of rivers deserted river courses are not unfrequent as that of the Serio Morto which formally fell into the adda in Lombardy the Pau also itself has often deviated from its course aving after the year 1390 deserted part of the territory of Cremona and invaded that of Parma its old channel being still recognizable and there in the name of Pau Morto there is also an old channel of the Pau in the territory of Parma called Povecchio which was abandoned in the 12th century when a great number of towns were destroyed artificial embankments of Italian rivers to check these and similar aberrations a general system of embankment has been adopted and the Pau, Adige and almost all their tributaries are now confined between high artificial banks the increased velocity acquired by stream thus closed in enabled them to convey a much larger portion of foreign matters to the sea and consequently the deltas of the Pau and Adige have gained far more rapidly on the Adriatic practice of embankment became almost universal but although more sediment is born to the sea part of the sand and mud which in the natural state of things would be spread out by annual inundations of the plain now subsides in the bottom of the river channels and their capacity being thereby diminished it is necessary in order to prevent inundation in the following spring to extract the matter from the bed and add it to the banks of the river hence it happens that these streams now traverse the plain on the top of Imon's like the waters of aqueducts and at Ferrara the surface of the Pau has become more elevated than the roofs of the houses the magnitude of this barriers is a substitute of increasing expense and anxiety it haven't been sometimes found necessary to give an additional height of nearly one foot to the banks of the Adige and Pau in a single season the practice of embankment was adopted in some of the Italian rivers as early as the 13th century and Dante writing in the beginning of the 14th describes in the 7th circle of hell a rivulet of tears separated from a burning sand in desert by embankments like those which between Ghent and Bruges were raised against the ocean or those which the Paduans has erected along the Brenta to defend their villas on the melting of the Alpine snows Quali fiammighi traguzzante e Bruggia temendo il fiotto che in verlor savventa fanno lo schermo perché il mar si fuggia e quali padovan lungo la Brenta per difender loro villi e loro castelli anzi che carintana il caldo senta Inferno canto 15th in the Adriatic from the northern part of the Gulf of Trieste where this also enters down to the south of Ravenna there is an interrupted series of recent accessions of land, more than 100 mesing length, which within the last 2000 years have increased from 2 to 20 mesing breadth. A line of sandbars of great length has been formed nearly all along the western coast of this Gulf which are lagoons, such as those of Venice and the large lagoon of Comacchio 20 miles in diameter newly deposited mud brought down by the streams is continually lessening the depth of the lagoons and converging part of them into meadows the isonzo, tagliamento, piave Brenta, Adige and Po, we said many other inferno rivers contribute to this advantage of the coastline and to the shallowing of the lagoons and the Gulf Delta of the Po the Po and the Adige may now be considered as entering by one common delta for two branches of the Adige are connected with arms of the Po and thus the principal delta has been pushed out beyond those bars which separate the lagoons from the sea the rate of the advance of this new land has been accelerated as before stated since the system of embarking the rivers became general especially at that point where the Po and Adige enter the waters are no longer permitted to spread themselves far and wide over the plains and to leave behind them the larger portion of their sediment mountain currents also have become more turbid since the clearing away of the forests which once clothed the southern flanks of the Alps it is calculated that the mean rate of advance of the delta of the Po on the Adriatic between the years 1200 and 1600 was 25 yards or meters a year grass the mean annual gain from 1600 to 1804 was 70 meters Adria was a seaport in the time of Augustus and had in ancient times given its name to the Gulf it is now about 20 Italian miles in land Ravenna was also seaport and is now about 4 miles from the main sea yet even before the practice of embankment was introduced the alluvium of the Po advanced with rapidity on the Adriatic For Spina, a very ancient city originally built in the district of Ravenna at the mouth of the great arm of the Po was so early as the commencement of our era 11 miles distant from the sea but although so many rivers are rapidly converting the Adriatic into land it appears by the observation of Amor Law that since the time of the Romans there has been a general subsidence of the constant bad of the sea in the same region to the amount of 5 feet so that the advance of the new made land has not been so fast as it would had been had the level of the coast to remain unaltered the signs of a much greater depression anterior to the historical period have also been brought to light by an Arthesian well bored in 1847 to the depth of more than 400 feet which still fade to penetrate through the modern Fruviati deposit yoga passed chiefly through beds of sand and clay but at four several deaths one of them very near the bottom of the excavation is the beds of turf of accumulations of vegetable matter precisely similar to those now formed superficially on the extreme borders of the Adriatic hence we learn that a considerable area of what was once land has a sand down 400 feet in the course of ages the greatest depth of the Adriatic between Dalmatian mouths of the Po is 22 fathoms but a large part of the Gulf of Trieste and the Adriatic opposite Venice is less than 12 fathoms deep farther to the south where it is less affected by the influx of great rivers the Gulf deep and sponsorably Donati, after dredging the bottom, discovered the new deposits to consist partly of mud and partly of rock the rock being formed of calcareous matter and crusting shells we also ascertained that particular species of Testacea were grouped together in certain places and were becoming slowly incorporated with the mud or calcareous precipitates Olivi also found some deposits of sand and others of mud extending halfway across the Gulf and he states that their distribution along the bottom was evidently determined by the prevailing current it is probable therefore that the final sediment of all the rivers at the head of the Adriatic may be intermingled by the influence of the current and all the central parts of the Gulf may be considered as slowly filling up with horizontal deposits similar to those of the sub-opening hills and containing many of the same species of shells the Po merely introduced at present fine sand and mud for it carries no pebbles farther than the spot where it joins the Trevia west of Piacenza near the northern borders of the basin Di Zonzo, Tagliamento and many other streams are forming immense beds of sand and some conglomerate for here some high mountains of Alpine limestone approach within a few miles of the sea in the time of the Romans the hot paths of Mont Falcone were on one of several islands of Alpine limestone between which and the main land on the north was a channel of the sea about a mile growth this channel is now converted into a grassy plain which surrounds the islands on all sides among the numerous changes on this coast we find that the present channel of Di Zonzo is several miles to the west of its ancient bed in part of which at Ronchi the old Roman bridge which crosses the Via Appia was lately found buried in Fruviati in Silt end of chapter 17 part 1 recording by Emanuella chapter 17 part 2 of principle of geology this is a LibriVox recording all LibriVox recordings are in the public domain for more information or to volunteer please visit LibriVox.org recording by Emanuella principle of geology by Charles Lille marine delta of the Rhône the Lacostrian delta of the Rhône in Switzerland has already been considered its contemporaneous marine delta described scarcely has the river passed out of the lake of Geneva before its pure waters are again filled with sand and sediment by the impetuous arb descending from the highest Alps and bearing along in its current the granite detritus annually brought down by the glaciers of Mont Blanc the Rhône afterwards received vast contribution of transport and matter from the Alps to the mountains of central France and when at length it entered the Mediterranean it discolors the blue waters of that sea with a whitish sediment for the distance of between 6 and 7 miles throughout which space the current of freshwater is perceptible Strabo's description of the delta is so inapplicable to its present configuration as to attest a complete alteration in the physical features of the country since the Augustan age it appears however that the head of the delta or the point at which it begins to ramify has remained unaltered since the time of Plignin for he states that the Rhône divided itself at all into two arms this is the case at present one of the branches the western being now called leptione which is again subdivided before entering the Mediterranean the advance of the base of the delta in the last 18 centuries is demonstrated by many curious antiquarian monuments the most striking of these is the great and unnatural detour of the old Roman road from Ugernum to Bezier Beterre which went round by name Nemausus it is clear that when this was first constructed it was impossible to pass in a direct line as now the delta and that either the sea or marshes intervening in a track now consisting of terra firma Astro also remarks that all the places on low lands lying to the north of the old Roman road between Nim and Bezier have names of Celtic origin evidently given to them by the first inhabitants of the country whereas the places lying south of that road toward the sea have names of Latin derivation and were clearly founded after the Roman language had been introduced another proof also of the great extent of land which has come into existence since the Romans conquered and colonized Go is derived from the fact that the Roman writers never mentioned the thermal waters of Bararoc and the delta although they were well acquainted with those of ex and others are still more distant and attached great importance to them as they invariably did to all hot springs the waters of Bararoc before must have formally issued under the sea a common phenomenon on the borders of the Mediterranean and on the advance of the delta they continued to flow out through the new deposits among the more direct proofs of the increase of land we find that Mies described under the description of Mesoacollis by Pomponius Mela and stated by him to be near an island is now far inland Notre-Dame-de-Port also was a harbor in 898 but is now a leak from the shore Psalmoudi was an island in 815 and is now two leaks from the sea several old lines of towers and sea marks occur at different distances from the present coast all indicating the successive retrieved of the sea for each line as in its turn become useless to mariners which may be well conceived when we state that the tower of Digno erected on the shore so late as the year 1737 is already a mile remote from it by the confluence of the Rhône and the currents of the Mediterranean driven by winds from the south are often formed across the mouths of the river by these means considerable spaces become divided off from the sea and subsequently from the river also when it shifts its channels of efflux as some of these legumes are subject to the occasional ingress of the river when flooded and of the sea during storms they are alternately salt and fresh others after being filled with salt water are often lowered by evaporation till they become more salt than the sea and it has happened occasionally that a considerable precipitate of muriat of soda has taken place in these natural sultans during the latter part of Napoleon's career when the excise lows were enforced with extreme rigor the polis was employed to prevent such salt from being used the fleuvietil and marine shells enclosed in these small lakes often live together in brackish water but the uncongenial nature of the fluid usually produce a dwarfish size and sometimes gives rise to strange varieties in form and color Captain Smith in his survey of the cost of the Mediterranean found the sea opposite the mouth of the Rhône to deepen gradually from 4 to 40 fathoms within a distance of 6 or 7 miles over which the discolored freshwater extends so that the inclination of the new deposits must be too slight to be appreciable in such an extent of section as a geologist usually obtains in examining ancient formations when the wind blew from the south west the ships employed in the survey were obliged to quit their moorings and when they returned the new sand banks in the delta were found covered over with a great abundance of marine shells by this means we learn our occasional bets of drifting marine shells may be coming to stratified with a freshwater strata at the river's mouth stony nature of its deposits at a great proportion at least the new deposit in the delta of the Rhône consists of rock and not of losing current matter is perfectly assertant in the museum at Montpellier is a canon taken up from the sea near the mouth of the river embedded in a crystalline calcareous rock large masses also are continually taken up of an arenaceous rock cemented by calcareous matter including multitudes of broken shells of recent species the observation lately made on this subject corroborate the former statement of Marsili that the earthy deposit of the coast of Langdok form a stony substance for which reason he ascribes a certain bituminous saline and glutinous nature to the substances brought down with sand by the Rhône if the number of mineral springs charged with carbonate of lime which fall into the Rhône and its feeders in different parts of France be considered we shall feel no surprise at the lapidification of the newly deposited sediment in this delta it should be remembered that the fresh water introduced by rivers being lighter than the water of the sea floats over the latter and remains upon the surface for a considerable distance consequently it is exposed to as much evaporation as the waters of a lake and the area over which the river water is spread at the junction of great rivers and the sea may well be compared in point of extent to that of considerable lakes now it is well known that so great is the quantity of water covered off by evaporation in some lakes that it is nearly equal to the water flowing in and in some inland seas as the Caspian it is quite equal we may therefore well suppose that in cases where a strong current does not interfere the greater portion not only of the matter held mechanical in suspension but of that also which is in chemical solution may be precipitated at no great distance from the shore when these final ingredients are extremely small in quantity they may only suffice to supply crustaceous animals, corals and marine plants with the earthy particles necessary for their secretions but whenever it is in excess as generally happens if the basin of a river lie partly in a district of active or extinct volcanoes then will solid deposits be formed and the shells will at once be included in a rocky mass coast of Asia Minor example of the advance of the land upon the sea are afforded by the southern coast of Asia Minor Admiral Sir F. Belfort has pointed out in his survey the great alterations affected since the time of struggle where heavens are filled up islands join the mainland the whole continent has increased minimizing extent struggle himself on comparing the outline of the coast in his time with its ancient state was convinced like our countrymen that it had gained very considerably upon the sea the new format strata of Asia Minor consist of stone not of losing current materials almost all the streamlets and rivers like many of those in Tuscany and the south of Italy hold abundance of carbonate of lime in solution and precipitate travertine or sometimes bind together the sand and gravel into solid sand stones and conglomerates every delta and sun bar does acquire solidity which often prevents streams from forcing the way through them so that their mouths can reach in the position delta of denial that Egypt was the gift of denial was the opinion of her priests before the time of Herodotus and Reynolds observes that the configuration and composition of the lowlands leave no room for doubt that the sea once washed the bays of the rocks on which the pyramids of Memphis stand the present bays of which is washed by the foundation of denial at an elevation of 70 or 80 feet above the Mediterranean but when we attempt to carry back our ideas to the remote period when the foundation of the delta was first laid we are lost in the contemplation of so vast an interval of time Herodotus observes that the country around Memphis seemed formally to have been an arm of the sea gradually filled by the Nile in the same manner as the Mende, Echelos and other streams had formed deltas Egypt therefore he says like the Red Sea was once a long narrow bay and both gulfs were separated by a small neck of land if denial he adds should by any means have an issue into the Arabian Gulf it might chuck it up with Earth in 20,000 or even perhaps in 10,000 years and why may not denial have filled greater Gulf with mud in the space of time which has passed before our age the distance between Memphis and the most prominent part of the delta in a straight line north and south is about 100 geographical miles the length of the base of the delta is more than 200 miles if we follow the coast between the ancient extreme eastern and western arms but as these are now blocked up part only of Lower Egypt which intervenes between the Rosetta and Amietta branches is usually called the delta the coastline of which is about 90 miles in length the bed of the river itself says Sir J.G. Wilkinson undergoes a gradual increase of elevation varying in different places and always lessening in proportion as the river approaches the sea this increase of elevation in perpendicular height is much smaller in lower than in Upper Egypt and in the delta it diminishes still more so that according to an approximate calculation the length about 11,000 or the first cataract latitude 24°5 has been raised 9 feet in 1,700 years at these latitude 25°43 about 7 feet and at Heliopolis and Cairo latitude 30° about 5 feet 10 inches at Rosetta and the mouth of the Nile latitude 31°30 the diminution in the perpendicular thickness of the deposit is lessened in a much greater decreasing ratio that in the straightened valley of Upper Egypt or wind to the great extent east and west over which the inundation spreads for this reason the alluvial deposit does not cause the delta to protrude rapidly into the sea although some ancient cities are now a mile or more inland and the mouth of the Nile mentioned by the early geographers have been many of them silted up and nearly changed it the bed of the Nile always keeps pace with the general elevation of the soil and the banks of this river like those of the Mississippi and its tributaries are much higher than the flat land at a distance so that they are seldom covered during the highest inundations in consequence of the gradual rise of the river's bed the annual flow is constantly spreading and crutches on the desert covering to the depth of 6 or 7 feet the base of statuaries and temples which the waters never reached 3000 years ago although the sands of the Libyan deserts have in some places been drifted into the valley of the Nile yet these aggressions, says Wilkinson are far more than counterbalanced by the fertilizing effect of the water which now reaches farling lands toward the desert so that the number of square miles of arable soil is greater at present than at any previous period mud of the Nile on comparing the different analysis which have been published of this mud it will be found that it contains a large quantity of argilaceous matter with much peroxide of iron some carbonate of lime and a small proportion of carbonate of magnesium the latest and most careful analysis by Emla Sein shows a singularly closer resemblance in the proportions of the ingredients of silica, alumina iron, carbon lime and magnesium and those observed in ordinary mica but a much larger quantity of calcareous matter is sometimes present in many places, as at Cairo where artificial excavations have been made or where the river has undermined its banks the mud is seen to be thinly stratified the upper part of each annual layer consisting of earth of a lighter color than the lower and the holes separating easily from the deposit of the succeeding year these annual layers are variable in thickness but according to the calculations of Girard and Wilkinson the mean annual thickness of a layered Cairo cannot exceed that of a sheet of thin pasteboard and a stratum of 2 or 3 feet must represent the accumulation of a thousand years the depth of the Mediterranean is about 12 fathoms at a small distance from the shore of the delta it afterwards increases gradually 250 and then suddenly descends to 380 fathoms which is, perhaps the original depths of the sea where it has not been rendered shallower by fluviatin matter we learn from Newton and Newbold that nothing but the finest and lightest ingredients reach the Mediterranean where it has observed the sea discolored by them to the distance of 40 miles from the shore the small progress of the delta in the last 2000 years perhaps no measure for estimating its rate of growth when it was an inland bay and had not yet protruded itself beyond the coastline of the Mediterranean a powerful current now sweeps along the shores of Africa from the straits of Gibraltar to the prominent convexity of Egypt the western side of which is continually the prey of the waves so that not only are fresh accessions of land checkered but ancient parts of the delta carried away by this cause Canopus and some other towns have been overwhelmed but to this subject I shall again refer while speaking of tides and currents end of chapter 17 part 2 recording by Emanuela