 Anyway, it's a pleasure to welcome Richard Little back today. He's a professor emeritus of geology at Greenfield Community College, and he's been exploring the geology of our region for the past 50 years. He's the discoverer of the rare armored mud balls in the Connecticut Valley. Yes, Maya, when you say that. Yeah. What is a rare armored mud ball? And he's written a book and produced two videos on the local geology. And he has one of his books up here for sale. We should buy one later. Richard Little also leads fantastic landscape tours and has a website which is earthviewasoneword.rocks, correct? And are there listings of your activities? Yes, you'll find all sorts of stuff there. Great, so it's up to you. Thank you. Thank you. So we're doing like a half billion years of history today, so how long will you stay? Until Sunday at 2. Okay, Sunday until 2. I think everybody wants to be out of here by 1 o'clock, right? It's not about right. If you have to leave earlier, go ahead. I'm going to go through things fairly quickly, but I'm hoping to end up with a few minutes to spare so you can come up and at least have your chance to see, hold and appreciate the rare armored mud balls. This one's been cut on a rock saw, by the way, because it used to be. Hold. Now it's happening. So anyway, let's find out what all these things are about. And we're going to go into the deep history of Amherst and Drosemite today. And I do have a book that I'll tell you about in just a minute, but just so you know, it's $15, which isn't as best as you can get it. I paid the tax for you. He's not very nice. So let's go on and see what we have here. There's an advertisement because I newly towards this G.G.U. is saying, so we go all over the place, actually, from Scotland to Iceland to the national parks of the Southwest. So just to let you know what's coming up here, we're doing Iceland in 2020. We do have a few more spaces left. Jeff Valley in January, Hawaii in March. There's the two spaces left if you want to go to Hawaii and see all the new eruptive phenomena there. Yellowstone in then Scotland in September. And we've got about six spaces left in Scotland. So anyway, get on my email list if you wish. And if you don't get on the list today, because they had up front here, just email me. There's also a handout today. I made 15 copies. They may be gone. If you didn't get a copy and you blend these others, if for some reason you want a copy, just email me, and I will electronically send it to you. If you do email me without my official address, you can always do a Google search and make sure you say Richard Little Geologist, otherwise you'll get Little Richard. There's some rocks up in there. But also, I have my book for $15. The DVDs are left in my truck, which is like a half a block away. So if you want those, I can walk you over and get them. But we do have a special on these DVDs, $5 each, but today they're two for $10. So let's go back to the program. We're back from Iceland just this past June. And you know, one of the places I love to go in Iceland and everybody goes there, if you go to Iceland, you'll take this tour that will take you out here. But this is the Stroker Geyser. It's the prettiest geyser in the world, because you can stand right up next to it and it comes out of a pool and it just comes up and up and up and up right in front of you. Isn't that something? And then if you keep watching it goes back in. How long does it come up? It does it every five minutes. So, you know, if you've been an old faithful and you happen to have missed it, you'd wait an hour and a half, but here, oh, let's take it from this side. Let's take it from that side. But I'll give you a big hint. Where the water is wet on the path, do not stand there. And it's tempting to do that because everybody is over on this side and they say, well, let's go away from the crowd and get it from here. But of course, that's where the water rains down on you right there. It's boiling. You do not want to be over there. Anyway, that's the Stroker Geyser and come to Iceland if you can with me or just get there on your own. I also give advice, by the way, if you are going someplace that I typically go to. I'll tell you where to go. If you're too annoying, I'll really tell you where to go. So anyway, let's go back to the program. That's what it is about today. I want you to remember this. It's the best place in the world to study geology. And let's see why. Look at this overview of the area. There's a lava flow. That's the Holyoke Range. You all recognize where we are here. The Amazon is just out of the picture. But there's the Oxbone over in Holyoke. And dinosaur footprints and sedimentary rocks. A little bit like Hitchcock. It's the best place in the world to study geology. Now, this is a talk at the Historical Museum. And you guys deal with time here. But let's take a look at the deep time. We call it geologic time. The age of the earth is 4.5 billion years old. But do you know how much a billion really is? It's a lot. So here's my way of introducing this to you. How much time is 1 billion seconds? So there they are. 1 billion seconds. Give me a guess from the audience. A billion. How many years? 40 years. That's really close. It's actually about 31 years. But over 30 years. That's a billion seconds. That's a lot. And so when you start talking about billions of dollars and now trillions of dollars, that's 1,000 billion. I mean, talk about mind borrowing. It really is. 10 years to drift confidence and evolve life. And so there's a lot of time, even when it only says 4.5. So has there been a lot of changes? Of course. Lots of changes on life and the land, et cetera, et cetera, et cetera. So there we go. And so going on. The tectonic system here, the crust is drifting around and you probably have all heard about plate tectonics, I am sure. They're going to squeeze up everything that was in the ocean in between and that's going to be where Amherst was a while ago up in the mountains. So we'll talk about that story next. So in any event, this is the best place in the world to study geology. It's just laid out right across the valley. And many of you probably know bits and pieces of this story, but let's go on and find out more. So where are we? Map of Amherst, of course. And you like to do Google Earth? You like to do Google Earth? Okay. And the kind of my funny story about Google Earth is I remember the exact moment that I went from dial-up to cable. You ever try to get Google Earth on dial-up? And then all of a sudden it popped in. Well anyway, so here we are at the intersection of route 9 and 116 right up in here and I'm going to talk to the Hitchcock Center. You probably know where that is down over here. So we are right in the middle of Lake Hitchcock here. The old Glacial Lake. And so Glacial Lake Hitchcock to shoreline if you know your contours is around 250 feet above sea level and if we take a look at where we are you know we're right here on this little bump right there. So we're an island in the lake. That's Amherst College's bump right there. So there's Mount Warner. There's Amherst College on this little bump. And so we came up the hill and so we're somewhere like right in here. UMass a little bit further over there. If we take a look at that picture this is the floor of the old lake. That flatness is where the fields are. And then see these bumps here? That's part of the island and those are made up with something called drumlands which we'll talk about in just a bit. So the lake shore goes right along here like right around the roof of the Mallin Center and then there's the island that you were just seeing on that previous map. Well what are drumlands? Drumlands are glacial till. The ice went over the glacial till and it shaped it. So you might think of it as kind of like what waves do to sand. They make ripple marks. Well when glaciers come along they are a series of hills that are oriented in the direction of the glacier flow and they tend to be steeper on the up glacier side and more gentle on the down glacier side. But they're oriented. You see they're oriented in the direction of the glacier flow. Let's take a closer look. Topographic map once again. Look at these nice little hills that we see here, here, here. Amherst College is on one. Here. So you see we're on the side of the drumlands here and they extended above the level of Lake Hitchcock. So those were just a bunch of drumlands. The Hitchcock Center is on the drumland right at the shoreline so they look out from that vantage point across the lowlands of the Amherst Valley here and that's the bed of Lake Hitchcock. Almost totally the way it was when the lake drained 14,000 years ago. And boom, there it was. Big, flat, swampy land. So anyway, Hitchcock Center, us pulling out range and there's the lake has made quite a difference in the final shaping of our topography. So if we were here way back then we could have looked at the surrounding lake and the ice was melting away and as you can see the old lake bottom kind of surrounds us here and we're on these islands of drumlands. So anyway right outside the historical society, if you looked up to the north there would be the ice melting away there would be the icebergs coming down the lake kind of ramming into the shoreline here because the ice is still so close and this is of course a place that you will go in Iceland if you come with me. Anyway, great stories are in rocks and landscapes, right? That's my big claim of interest here in the world is to tell people about these great stories and I assure you Ok, so studying geology will help you read these great stories let's go on. Do you know there's only three types of rocks how many people have had a geology course you know about the igneous, the metamorphic, the sedimentary so the igneous rocks will once molten everything gets eroded to sediment eventually and that becomes sedimentary rock metamorphics change by heat and pressure if it's stuck in a collision of continents for instance so let me tell you about this important igneous concept so if you look at the igneous rocks you can either be deep down here in a magma chamber where there's very cool very slow cooling or you can be erupted quickly and be a lot of flow where the cooling is very quick so what's the difference great history here but what's the difference? Boy, they look so different because a lava flow is called extrusive an example would be basalt and basalt is kind of a dark ugly rock many times you see it as crushed stone all over the place and it's not very attractive but if you can slow cool it in a magma chamber for perhaps a million years then the elements come together to make minerals bigger sizes and you have things like granite not a really great granite picture but many of you probably have granite on your countertop something you could really enjoy looking at because you can see all the crystals that formed as they cooled deep in a magma chamber over maybe a million years now we're going to go back into deep time here so if you put the geologic time scale across your body with your outstretched hands you will see that we're going to skip the first 80% pardon me and we're going to go right to the paleozoic so the paleozoic time is closer towards where we are today than the beginning of the earth but there's fossils and we know so much more about the later history than we do about the earlier history just like with human history so if we go to the paleozoic era starting around 600 million years ago where were we well North America was on its side the east coast zone of North America was south of the equator now in this drawing they put the great lakes in Hudson's Bay but that's just to orient North America these were not here in the paleozoic but the big story for us is New England isn't even here yet the edge of North America was over around Albany and up to Lake Champlain so New England is not even here yet but there's a series of islands that come and crash into North America and these islands are going to go by plate tectonics and eventually collide with North America now when they do that they have to pass over the ocean crust because with plate tectonics these pieces are moving one relative to the other the ocean crust has to go down out of the way it's a process known as subduction so how are you folks on your geology training have you heard about subduction before great so that's the process the continental crust is lighter it flows higher in the earth than the ocean crust and so it's able to push over the ocean crust the ocean crust goes down that's subduction now I would like to share with you the world's only subduction joke if I may and so here it is you're all seeing subduction in a totally different format there's the duck on a pond that is subduction so that's kind of an interesting joke I think because the process is similar to what we have in geology where you have something going down underneath something else so subduction there it is can you ever forget that so here we are these plates are coming towards North America it's subduction going on and then we get collisions as they come closer and closer and merge with North America but if you were here at this time and were to look around at our landscape there are erupting volcanoes and earthquakes just like the Pacific North we could have landscapes just like this here old volcanoes the ocean was nearby maybe a crater lake so that was our landscape here because we're on a subduction zone you know this is a piece of land that's moving towards North America and we're on the subduction zone well let's take a look at where North America itself is going to go here 750 million years ago which is Lake Precambrian we were right next to this what is now a separate continent but North America and you never guess this but geologically as they trace the path of North America our east coast part of North America actually scrapes around and goes to the west coast of South America and finally crashing into North Africa right up there that's how we fit together and we get the super continent of Pangea and the Appalachian mountains are the result of the collision and so there we are a great story but what's the evidence and indeed it comes from rocks if you look at the rocks from that collision they are all squeezed up deep in the earth now exposed by erosion but deep in the earth it's a rock like this this was from Shelburne Falls but it's a rock called NICE so I don't have time to talk too much about this in detail this is my pet rock today it's a NICE you can see layers here light and dark but they're not sedimentary layers they're mineral layers and so I call this my pet rock it's not just a NICE from deep in the earth it's a NICE that preserves an earthquake dum can you see that the layers don't quite line up look at that see they don't quite line up so when you break a rock that's a quake now whenever there's a crack in a rock fluids will tend to come through and resement it back together typically quartz will come in here so here is an old earthquake and one side has been cemented back to the other now you're going to say that what kind of an earthquake was that because the offset is only this much right but maybe when this cracked it was the result of movement from the world's biggest earthquake that was 100 miles away so you don't really know but there it is fossil earthquake in a metamorphic rock isn't that nice okay this is a from a glacial deposit that was under the french king bridge basically one or two one of my students found this and donated it to me so it's been my pet rock ever since but it's one of these guys here from the collision and the force of the collision in this nice rock you can see how banded it is and bent, I mean that's an artifact of this collision lots of compression now some other things you may not know about the evidence of the collision is this we have a lot of slate around what is the slate mean? it's a metamorphic rock but if you go back to its sedimentary origins this is mud in the old ocean before pangea see between every continent there's an ocean hey I bet you never realized that now you do and when you push the continents together the mud from the old oceans becomes the rocks that get squeezed up and perhaps metamorphos like we see here so the slate on your roof is the mud of the old ocean before pangea and then we have this nice white rock which you can buy today in big bags from lily and perhaps around your flower beds and that's marble marble is mud but it's got more calcium in it from plankton shells that filter down from that old ocean and so that's the origin of the marble of course there's a marble belt made from western Massachusetts into Vermont down into Connecticut and lily hey that's where you get that's where the marble is from lily there it's also in tombs by the way so if you had a tombs sometime you are having calcium perhaps from lily because that is run by Pfizer to get forward there now I shall tell you that you're not getting crushed rock directly it's a marble and they crush it they dissolve it and then they re-precipitate it to make it a little bit more pharmacy grade than just a crushed rock okay so that's the paleozoic and if you're having trouble remembering what's happening when paleozoic starts with P pangea starts with P so in the paleozoic we have pangea creation of pangea and when we think about pangea it happened in the paleozoic so these pieces came together we made the Appalachian mountains that's the paleozoic today we're quickly going into the mesozoic now when we go to the mesozoic we're going to break pangea and you can remember this because whenever you break something you make a mess so we're going into the mesozoic okay that's kind of lame isn't it but anyway in the mesozoic we break pangea so let's take a look at the break this is really important for us sitting right here today pangea broke there was a whole series of cracks that made these rift valleys the biggest one happened where the Atlantic Ocean is today but we have this big crack also that goes right through our valley and you can trace this crack called the eastern border fault all the way from Keen, New Hampshire down to New Haven the distance from top to bottom is around 30,000 feet so think about that it doesn't mean that the valley was 6 miles from bottom to top at one time because it keeps filling in but the total drop was 6 miles from it so it was a big crack but it wasn't big enough for the ocean to come in here so we didn't get the ocean well we got a big crack nevertheless and into this big crack there come sediments now here's a rift valley from out west and if you take a look at the dynamics here the shapes here, the landscape shapes so we have the mountains the fault line is right on the base of the mountain so you see the valley drops down and then the rain comes out of the mountains the rivers come out of the mountains into the valley and they deposit sediments here in a big fan shape so we have the alluvial fans up against the mountains shorelines and lake beds another place that I really love to go is death valley but in the winter, not in the summer you don't plan your trip to death valley but it's a rift valley the whole western part of our country is breaking up it's below sea level here but even a little bit further south in Palm Springs it's below sea level and if you take another hop, skip and a jump you land in the ocean at the Sea of Cortez you know just off of Mexico there in Baja California so the ocean is on its way in so if you want a prime chance to buy shorefront property somewhere in here there in here the ocean will be here so in any event let's take a look at the rift valley so there's the mountains we have the fault line the alluvial fan shorelines and lake beds right here but they're dry so all these things are just displayed right here and I love going to death valley because it reminds me of the Mesozoic Connecticut Valley but it doesn't have hungry dinosaurs so we see the landscape and it's safer if you take a look at the geology of how we know all of this if you're on the alluvial fan you've got gravelly rock it's called conglomerate if you're on the shoreline you've got sandy rock if you're on the lake bed you've got muddy rock shales and when the shales when the mud dries up it can even preserve raindrops you see those little circles there that's raindrops individual drops 15 years old and then the mud dried and these are the remains of the mud cracks they've been filled with sand but that's the cracking of the mud so there's a weather forecast from 200 billion years ago okay so the Mesozoic is famous for guess what's going to be the next picture of course dinosaurs now the dinosaurs in our valley here those not Tyrannosaurus rex because we are in the leading to early middle of the Mesozoic so we're in what's called the late Triassic and early Jurassic so we're in the early Jurassic for most of our valley and this is the dinosaur called Dolophosaurus left Prince up and down the valley all over the place here's the famous one in Polio on a root 5 and 10 there a root 5 I guess it is and this one is quite famous because the only dinosaur in the world so a student that drew this cartoon and said well just like today there was a big social life in the valley so they all came to dance now dinosaur footprints and dinosaurs everyone's heard of them but put that into an ecological context this was a rich valley with plants and water sources rivers and lakes and a lot of fossils besides the dinosaurs but there are the reptiles amphibians and fish, plants, crustaceans and a lot of insects that burrowed their way through the rocks leaving tracks and traces and a lot of plants but we don't see a lot of plants because they decompose to our rapidly so the plants are not represented in the fossil record as much as they would have been when they were here living and now the amazing story of Armored Mudballs is everybody awake for this? so Armored Mudballs what are they and how did they get discovered well that's a six inch ruler for scale I came here from California when I got my job in Greenfield and was exploring down by the river in Turner's Falls so we were at Unity Park so when I got to the river there was a park I looked out my car window and I saw this foundation that's cemented in here with some nice rocks on the top there but I saw those circles now I know all of you would have gotten out of your car and walked five steps and said huh what is that? well when you look at this that's mud now stone of course it's set in a gravel which is an old river deposit and so I said well that's an Armored Mudball as the mud ball rolls downstream it gets soft, rounded, sticking on the outside as it continues to roll it picks up pebbles that just stick in the ball that's what we call the armor okay the dime was put there just for scale but I really wish I could find an Armored Mudball with a dime in it I would date it really really well wouldn't it? that would be quite the story but you can see the structure here so here's your river deposit pebbles that are just stuck in the outside once again that's the armor and there's kind of a sandy mudball what got them rolling? what's that again? what got them rolling? what got them rolling? they were just eroded by the stream so you can imagine a stream dead with layers of hard mud that might be 10, 20, 50 years old whatever but hard, hard mud not soft, super mud and then as the stream is cutting back see these are all 200 million years old so the mud chunks would have fallen in the stream and just tumbled downstream so anyway you now know what Armored Mudballs are and I'm going to move on to some recent Armored Mudballs so here are Armored Mudballs that are probably not going to be preserved because they were rolled out in the Farmer's Field in California and then the sun's going to come out and it's going to start operating probably but I just wanted to show you that Armored Mudballs are being formed today but the trick is to get them in the fossil record, in the rock record now a fellow who lives near here his name is Will Silin he's an artist, he's done a beautiful artwork at the Benesque Museum and other places but Will likes to go out west and hike, take pictures of the desert landscapes and then come back to his studio in Utah. Now how many people have been at factory views? Okay, I've never heard of it either but you know over the past year I've had three people raise their hands and said that they have been there which I thought was pretty surprising I guess I'm missing something so anyway, Will starts his walk and sees Armored Mudballs that have rolled out right there beside the trail these are about a foot high and there's the mud drying up you see so I thought that was incredibly amazing and about the same time I was at Guadalupe Mountain National Park which is right near Carlsbad Caverns, New Mexico you know where we are now out there, New Mexico and Texas come together there so I'm at Guadalupe Mountain and there was a big flood eight months earlier one of the limestone mountains here up to the left down this canyon you can see all the white colored rubble here these are all limestone blocks that were tumbled by the flood so it was a really pretty significant event so they have a nature center there and I'm walking along a paved path right from the nature center and I spy an Armored Mudball did you see it? so I'm walking along the path and I say wait a second so that's my wife of scale there so we went over to investigate and sure enough there it is, there was an Armored Mudball there was only one and I could not for a life of me figure out how in the midst of all that tumbling of the limestone blocks where the mud came from because I never saw any outcrops of mud up the little channel there I didn't get a chance to go too far up but it survived the flood there was a bank and there it is an Armored Mudball I was absolutely stunned was that recently formed or is that very old? no this is recent so that will fall apart so why did you just, I missed is it only ten places in the world there's only ten places in the world where Armored Mudballs are preserved in the rock in the rock I'm turning up the places and turning up the falls is one of them so anyway this was March 2015 and then I had a chance to do this same trip the next year so I bet you'd like to see what it looks like one year later so there it is so if I had seen it a year later I don't think I would have recognized it but there it is anyway that's the Armored Mudball story so this is actually a historical picture of me back in the 1980s I still have those pants that's a shame there were something these days so anyway here's the river this is Unity Park and the reason why this foundation was here is because this is a painting there was a suspension bridge across the Connecticut River from Turner Falls Unity Park over to Gill today if you go to this area it's flooded it's called Barton Cove and you know where they put the barrels across the barrels to keep people from going over the dam and the waterfall the barrels are right at the spot of that bridge so anyway you can follow this suspension cable which has to come down into an anchor and this was the anchor right into this so that was one of the suspension cable anchors so these rocks were quarried in the late 1800s and they were quarried locally right from Turner Falls and it was just lucky that they were quarrying these layers that had Armored Mudballs because they took the low rocks with the mudballs out and placed them and we can get them now so the town of Turner Falls gave us permission to take this down and preserve the specimens of importance and so we have the Greenfield Community College there's also some still at Unity Park so if you go to Unity Park you can see some pieces there but those abutments foundation level now dismantled at GCC we have a new geology path and the Armored Mudballs are in their own little section right there so if you come up to GCC you can find this it's not like going to UMass we have like one big brick building and this is right next to the subtly edge of that big brick building okay so back to the show show here we're splitting Panjia and when we split Panjia lava comes out it's called flood basalts just floods over the landscape but no big volcanoes so the continents are splitting and this is from Hawaii this is from Iceland not the place that we saw but it's from the internet this is an Iceland eruption which has a similar type of thing is what we would experience here so the basaltic lava is just coming out of these cracks and flooding like a flood over the landscape there might be some small volcanoes like spatter cones and maybe some cinder cones that are only a few tens of feet high but not a big volcano this is one of the big misconceptions I think people have about our holy oak range lavas so this is what the Mesozoic would have looked like right here in the Amherst area covered by this big sheet of lava but no big volcanoes now if there were big volcanoes here this is what you'd expect to see the ancient volcano itself would have been eroded but we would still see the harder parts of the structure of the volcano we would see things like this nothing like this up and down the Connecticut valley so what we have is a lava flow and there is a kink in this lava flow today it forms a ridge line and I should tell you it forms a ridge because the lava flow initially came out flat almost like a sedimentary layer it comes out flat as it floods across the land but remember the eastern borderfall how are you doing? the eastern borderfall tips everything down to the east so the main trend of the holy oak range is dipping towards the eastern borderfall and so when you tilt these layers and then you road them the hard part of these layers would be the basalt and that's going to just stick up so that's what we see here is a tilted layer and then you re-road the weaker rocks around it and so it sticks up because it is just harder but let's find out why it has this hockey stick bend in Amherst because everybody is interested in that we have this east-west part with the ranges over here well when the eastern borderfall went down it also regged laterally and so the seven sisters I think you're familiar with those tips in the range each one of the little valleys is a fault line and the fault lines are weaker than the areas in between the faults so you got these little faulted offsets because of the wrenching around as we come close to the eastern borderfall that's over there on our 1-16 the whole thing wrenched laterally and it broke up into a series of faults and the erosion like I said of those faults gives you the seven sisters but if you get a little bit further away from the borderfall there's a more traditional north-south dipping east structure of the Holy Oak Range so it's like a tilted book and this is a diagram from Connecticut but you can see the tilt here of the lava this is the Holy Oak Range this is the continuation into Connecticut and it keeps going and going and going it's broken up by some faulting right here around Hartford that's why it's so complicated but you can trace this all the way to New Haven the Holy Oak Range goes all the way that's got one lava flow goes all the way to that extent so it's an amazing event if you take a closer look at it there's Titan's Piazza right there looking south from Mount Shrugov have you seen the columns of Titan's Piazza perhaps these are not crystals this is just a cooling pattern in the basalt because it comes out liquid and it cools anything that cools will shrink so these are just shrinkage cracks that radiate down into the lava and then as you erode the lava pieces fall away and reveal the structure here just due to the cooling you've all seen this with mud mud does the same thing mud dries with cracks you get those excited mud cracks going down into mud but let me tell you something you didn't know in these columns you see relish circular structures like this so this is a great deal these are called pillow lavas and sometimes when the lava came out it flowed into lakes here in the old valley this is not Lake Hitchcock but 200 million year old valley and if you look closely at these this is one that hasn't been broken through but it almost looks like a pastry crust on the outside surface imagine almost 200 million year old liquid lava going into a lake it's going to cool quickly it's going to quench quickly and this is just where the surface is broken off so if you see basalt columns that means land if it flows into water it's going to be pillows and no it's not Lake Hitchcock now I'm going to show you a typical outcrop anyone been to Goat Peak across the river there's a anyway this is kind of an ugly looking rock but nevertheless you're looking at the Holy Oak Basalt and you might know that there's no columns here and if you look a little closer you can start to see little circular structures and that's a pillow lava so at that point this lava was flowing into a lake now if you did a hop skip and a jump less than a mile away you'd be at Titan's Piazza there are no pillows at Titan's Piazza so it means way back 200 million years ago you'd be standing in a lake here but a little further away you'd be on dry land because this is the same lava that came across right columns versus pillows and now we're going to test your interpretive skill we're on the Halfway House trail to the summit and here's the contact between layered sedimentary rock underneath and the lava what do you think columns or pillows okay it was columns okay let's get to the Ice Age quickly here how are we doing for time we can finish a normal spot but if you have to leave go ahead if you need a note for your employer so the last Ice Age we're really skipping up to the present because the last Ice Age was at its maximum only 20,000 years ago like whoa we're not talking billions anymore this was just yesterday so the Ice used to be way down here at Martha's Vineyard then tuck it out to George's Bank and on the other direction down to Juana Island so the Ice does erosion as it scrapes across the landscape scrapes and polishes rocky surfaces leaves bouldery soils behind and if you're on those bouldery soils you may have a snatch or stone wall in your backyard please note that the glacier didn't build the wall but it did bring the stones now we've got the Lake Hitchcock story here of course so where are the stones in Amherst down in the lowlands of Amherst where all the fields are here in surroundings you see the stones are there but they're under all the lake deposits because the lake came after the stones were deposited so the glacial tilt is down there but then when the ice melts back you've got a lake and you're going to bury the stones that you would find up here if you go up beyond the shoreline that's where you find the stone walls because once you hit the shoreline and below you don't find the stones because they're buried but I want to talk about deltas a bit because when rivers come into lakes they build deltas and deltas have a structure like this they have a flat top set part as the rivers build into and up to the lake shoreline but the more interesting part is that they're underwater the front of deltas are steep they're called foreset beds and as you go toward Sundaland here from Amherst to get the arrow direction you'd be going this way but as you go past Bub's Barbecue and you're going right across the front of a delta this is the exact picture of what you're going past on Lake Hitchcock the shoreline and the delta there's a gravel pit anyone know what the name of that gravel pit is? what? it's owned by the Warners but the company name is delta gravel you see it right on the side fish hatchery just across the road that's on the lake the clay of the lake floor you mind the gravel, that's the shoreline area but the bottom of the lake is more clay rich that's where the fish ponds are because you don't want the water to drain away so looking into the Warners gravel pit there, delta gravel you see these layers that are tilted towards you, those are the foreset beds that were deposited in the lake that would be the underwater part and then the top layers are flat those are the top set beds let's go to this gravel pit to illustrate this not the exact same one but similar structure you see how these layers are tilted if you didn't know about deltas and you knew a little geology you would say, oh my gosh, these used to be flat and there must have been big earthquakes to tilt them all up like this but no, this is just the natural deposit in a delta so when this delta was being built into Lake Hitchcock when the foreset bed was here the top set bed would have been there and that would have been the shoreline and then through time it builds out and out and out and up and up and up there's actually a delta, there's the stream flow so top set builds up there's the foreset build out and the shoreline is the contact between the top set and the foreset so geologists love to find these things because that will do an elevation measurement there and we'll get the shoreline and that's a cool story and now, this picture from Alaska there's the glacier, there's a nice tunnel from the melt water, there's the delta top and look at how muddy the lake is well, the muddy water is going to settle out mud is going to settle out of that water and it will have a yearly deposit here because in the wintertime when the lake is frozen the very finest sediments will have a chance to settle out, but in the spring and summer when the river is going fast it'll be more silty and so the next year we'll repeat it so every pair of layers is one year and it's called a var and so we have those in great numbers here bricks are made out of the clay by the way so if your town has a brick industry it's mining lake Hitchcock clays and in Greenfield there was the Prey family that ran the brickyard and so they put their name on a brick and when you see some of these old bricks I would tell my students, hey pick up that brick, there could be a message for you yes in Amherst it was ABC it was the Amherst Brick Company thank you for that because I found those ABC bricks right and I have one okay so anyway after Lake Hitchcock drained about 14,000 years ago the river can come back to its valley and it will cut these river terraces wind will blow across the old lake bed sand dunes so we find sandy layers across much of the old lake bed and so this is our landscape folks it's got an incredible history and wonderful soils the best place in the world to study geology and what has been seen and not be seen so that's the end some of you have to go but I'll take two questions and then I'll be here to answer anything else are there two quick questions? are they shouldn't have strawlands? no, that's bedrock are they going in the wrong directions? they're not too bad they're not too bad in terms of direction but there are drumlands on top of north sugarloaf you can see them on the map but drumlands that may have a racial till and sugarloaf is bedrock so it's just a bedrock well not cast or pollocks of drumlands I believe so okay, well let me just stop it right here then please come up if you're leisure see an armored mud ball buy a book if you want it'll fall I mean the rock