 Thank you Miguel for the presentation. Good morning everybody. I have to take the floor in this occasion but this paper will not be possible without Dr. Miguel Carrero, a researcher from the University of Santiago in Leiden and a specialist in LiDAR analysis. As you perfectly know he's a part of the paper and I will read the whole presentation today. The aim of this paper is to analyze the links existing between the boroughs of the Salas Council in Asturias, northwest of Spain, very close to Galicia at the east part of this region. Sorry I don't have a map, my mistake. We try to analyze the relation between the boroughs and the quarries used for building these megalithic tombs. This line of research has been funded by the Valdez Salas Foundation, an institution which has a special interest in these archaeological remains. Well, our starting point is a database from the Seidson Monument Record carried out in 1990. Our efforts were focused on the boroughs that in this area concern neolithic and calcolithic chronologies between the 4300 BC and 2500 BC. Our lines of research, as you are seeing now, during the last two years were following the methodology applied and the first result of using LiDAR, the use of LiDAR for measuring the structures in volume and cubic meters and searching for the quarries linked with the boroughs. All of them were part of past meetings so we will be presented, I hope, at some of the next year's congress. Regarding this paper and the quarries, the number of structures examined were only 18. We did not analyze the whole 28 structures. The main topic of this paper is closely linked with the first question that you are seeing now on the slide, but regarding this idea new questions arise. For example, is the stone really necessary for building the megalithic tombs? Although there are several types of megalithic tombs during the Neolithic and Calcolithic of Asturias and not all of them require stones for building the tombs, the answer is affirmative, at least in the case of the examples involved in this paper. I would like to stress one example of the same area in order to clarify my point of view. TAMP number five of La Cobertoria in San Juan, Salas, which we had been digging in detail from 2016. Three different phases were discovered in the tomb that had been induced during five centuries, between 4000 BC and 3500 BC. Compared with the Pontic region, it looks an easy game to dig these kind of structures, not with all the use of the barrow along the time, like in all this area. Both the third and the first phases of La Cobertoria used enormous quantities of stone for the megalithic architectures, obviously at the level of the barrows in the northwest of Spain. In the third phase, stone was part of the tomb and it was not only used for building the burial chamber in the middle of the barrow. Several tons of stones were gathered from the surroundings to make the stone green at the border of the tumulus, as you are seeing now. In the first phase, around 4000 BC, a small structure was built previous to the dolmen. It's a circular stone tumulus, so we have here again the stone for the construction for building the tomb. What happens with the other barrows of this mountain? Information gathered from the site's monument record gives us evidence of the use of the stone in the barrows. For example, in the description of the composition of the barrows, number one, two, and four, the text and the photos included in the record, show clearly the presence of this material, at least as part of the accumulation that forms the tumulus. As regards the necropolis of Las Corradas, the evidence is less obvious and more indirect, but it's still clear. These groups of tombs were more affected by plantations and three structures were partially destroyed by a road opened in 1997-1998. It's the case of barrows number one, two, and three. As a result, today it's therefore possible to see part of the interior of the tumulus scattered across the profiles left by the road in the south part. Clear evidence of the stone appears in the profile and in the surroundings. The same types of processes were found on the other side of these three partially destroyed structures. Having said that, let's move to a wide vision of the necropolis that allow us to gather more data about the quarries, the case of San Juan. You are seeing now on the slide the distribution of the tumulus over the digital model of the terrain after applying some visualization techniques. Not far from barrows, a significant number of rocky outcrops were discovered during the field works. The outcrops are always of the same type of rocks used for the barrows, quartzite. This correlation was carefully checked by the geologists of the University of Obiedo, Dr. Álvaro Rubio-Ordones, especially in the case of barrow number five of the necropolis. It's necessary to stress that these logical links have always to be analyzed in terms of landscape, because in this particular example, barrows and quarries are part of the mountain, conforming groups of natural elements in geological or topographical terms. A good example will be the summit of San Juan crossed by a rocky outcrop along the whole mountain. The same situation can be pointed out in the other two slopes of San Juan, where lines of bedrock probably use as quarries in different degrees, arising several points of the hillside. As a consequence of the large number of rocks available, they possibly had different options during the construction of the tombs. It's totally clear, as we will see at the end, that prehistoric societies did not only take decisions based on functional terms, rites, superstitions, beliefs or traditions can be key points in order to take the final decision, but the efforts and the distance to cover from the barrows to the quarries are always key factors and for this reason they must be taken into account, especially in small communities like the Asturian case. Concerning the three main areas of San Juan, we will analyze each group along the following slides. Barrow number three is probably the most significant example of close connection between human construction and the possible quarry used for building it, less than 15 meters of distance between a large outcrop at the right of the image and megalithic tomb at the left. In other cases, the links are not so clear. The builders of barrow number four have several possibilities. For instance, quarries B and CD were pointed out in the analysis as the most probable sites for taking rocks. In the first case, the reasons were the small distance between tombs, the tomb and quarry, as well as the presence of huge rock emerging from the soil. The site called CD, in Spanish Peñas de Nubleo is the largest quarry of all the mountain and was probably a key reference in the landscape. The rocks are dividing areas showing relevance in the landscape due not only to the position but also due to its features. Cultural or symbolic reasons could work in this relation between Peñas de Nubleo and barrow number four in addition to the huge amount of rocks of great quality available in this part of the mountain. The last area of interest is linked with the most significant tumulus in the necropolis, barrow five called the cobertoria. Although there is apparently occupying a minor position in the mountain far from the summit of the hill, other reasons could explain the importance of the site for the prehistoric communities and the notably efforts developed during its three prehistoric phases. Between these reasons could be the remarkable abundance of big rocks in the surroundings. In 2016, less than 70 meters from the barrow, a clear front of a possible quarry invisible and clear connection with the barrow was identified. Again the same type of rocks in the quarry and in the megalithic burial chamber. It looks like the main site for quarrying due to its features and the distance. However, other secondary quarries could have been induced during the several phases where less remarkable blocks of rocks appear in the slope of the mountain which emerge from the soil discontinuously. It's the case of qi in the center of the image. Moreover, during the construction of a small road, the action of the bulldozer removed two enormous blocks of rock not far from the barrow number five, less than half a kilometer, called quarry g and quarry qi you are seeing in the pictures. Although they are natural rocks coming from the bedrock, it seems clear the possibilities of this bedrock along the slope to easily produce megalithic rocks. Finally, we will like to stress some preliminary results of the Corradas necropolis, an area that will need further fieldworks to confirm the initial proposals. But it seems clear that the first analysis in this mountain with certain barrows identified that the two main areas arose. Western and eastern sectors are clearly divided, conforming to physically separated subsets. Barrows one to three briefly described at the beginning of the paper on the western part, barrows four to seven in the eastern part. Both clusters of barrows were built in small flat areas divided by geological vertex. Moreover, the dividing line is the main quarry currently identified in the mountain, the site called Peña del Moro, still conserves some huge blocks of quartzite, the same type of rocks that appears frequently in the surroundings of the barrows one to three, as it was previously remarked. The eastern barrows of the necropolis are far from this block and we have to add another difficulties for researching all these areas, so further analysis will be necessary. LiDAR was useful to identify huge trenches in this eastern part, not far from the tumult. The neighbors of Las Corradas, the village, remember that the trenches were used as quarry for building repairing the houses of the village. In other words, we have an area with rocks and resources for building. To sum up, although further analysis will be necessary, we can stress some points. There are remarkable differences between the information provided by both cemeteries. More data have been gathered in San Juan where barrows are surrounded by rocky outcrops. However, barrows and quarries are in close connection in both cases, justifying the presence of rocks of different sites in the barrows of both cemeteries. Obviously, both must be considered and analysed in terms of the landscape due to the fact that geological elements and the topography made the territory divided itself, probably establishing differences between the three areas identified. We have to emphasise, too, the reasonable distance to the quarries in both cases. In San Juan, the range is very convenient between 15 meters and 185 meters of distance. This is a work in progress because only some functional variables were considered. During a second phase of our research, we will develop a software in order to precise the analysis. Different computer models will be built during further approaches to reconsider the connectivity between the mounds and the possible outcrops using GIS analysis. Agent-based models can introduce some variables, loads, age, landscape, characteristics, vegetation slope. This can be done using classical approach, let's go path from everywhere to everywhere, or the network analysis. To conclude, at this point of the research, it is impossible to measure some more complex variables to understand the precise points selected for quarrying. So additions or other cultural aspects must be always taken into account, obviously. In that sense, we have La Cobertoria as a great example of other reasons different from the distance working in the prehistoric communities of Asturias. Because the second phase of La Cobertoria shows an original megalithic design. A ring of red clay of 12 meters of diameter was built around 3700 BC following the thermoluminescence data available. Part of the clay was moved from the middle zone of the valley, at least more than a kilometer down the slope. The difference in altitude between the quarry or quarries and the tumulus is around 150 meters. Two sites, Gaginairo-Minal Arena, you have here, were identified by the local neighborhood as the only clay quarries in the territory. Both have the same color and features that the clay used to have in La Cobertoria. The three types of clay are very similar in composition, as the analysis has pointed out. Further analysis was developed as well in order to clarify these non-functional reasons for explaining the enormous effort of carrying tons of pure clay for building the tombs. That's all. Thank you for your attention.