# Autochthonous or Allochthonous, the Prehistoric Pottery of Cueva de Los Postes
## 4 Discussion
That the organic deposits are not concentrated on only one side of the two surfaces and are present only on some samples supports the hypothesis that the presence of organic deposits was not intentional but the result of post depositional action. In order to compare the clay that comprises the pottery and to understand if the supply of raw material was found near the cave or in the area adjacent to it, six sediment samples were taken. Two of these samples were taken from an old quarry located about 8 km from the cave. The quarry was used until the end of the last century as a supply of clay. Additional samples were taken in the cave, outside the cave, and in one of the other caves in the Fuentes de Leon park, the Cueva de Los Caballos. From observing the FTIR spectra of the six sediment samples (Figure 6), it is clear that they are not composed of the same material. Samples taken at the clay quarry of Vale dela Jara (JAR22/01 and JAR22/02) are not considered likely to be the same clay used for the creation of the analyzed pottery, but they are a part of the same mineralogical group, which is the kaolinite-serpentine group. The sample POS22/02, which was taken inside the Cueva de Los Postes, is quite different. It turns out to be a part of the geokaolinite-serpentine group, but it does not correlate with the composition of the analyzed pottery, something that can also be argued for the sediment sample JAR22/02. The sediment samples that are similar to the composition of the analyzed pottery are POS22/01, taken outside the cave, and JAR22/01. To make the comparison between the pottery and the sediments, the peaks that are typical of water found in the different clays (around values of 3000-4000+o-4 cm\({}^{-1}\)), and those typical of the different clay groups (between values of 900 and 1000+o-4 cm\({}^{-1}\)) were used to make this identification. All the pottery we analyzed show the typical peak of aluminum silicates between 980 and 990 cm\({}^{-1}\) with a range of +o-4 cm\({}^{-1}\) (Table 1). In Table 1, only the relative peaks of water and the main aluminum silicates peaks found in the clays are shown. From Table 1, it can be seen that the pottery samples which peak around 910-916 cm\({}^{-1}\) do not peak around 1000 cm\({}^{-1}\) and are therefore not comparable with the POST22/02, JAR22/02, CAB22/01, and CAB22/02 sediment samples. However, a particular comparison is evident between sediment samples JAR22/01, taken at the quarry, sample POST22/01, taken outside of Cueva de Los Postes, and some of the pottery shends (POST-3E, POST-4E, POST-7E, and POST-7I). These samples have peaks related to the aluminum silicates component around 985-999+o-4 cm\({}^{-1}\) and one around 910-916+o-4 cm\({}^{-1}\). An exception is made for sample POST-10I, which shows a pair of typical aluminum silicates peaks at 963 and 916 cm\({}^{-1}\) that were not found in the other analyzed samples. The two samples taken at the Cueva de Los Caballos, due to the particularly clayey composition of the cave, are both considered to be non-comparable with the analyzed pottery. Sample POS22/02, i.e., the one taken within the Cueva de Los Postes, is also not considered comparable to the analyzed pottery due to its high percentage of limestone (i.e., peaks at 1419, 872, and 712 cm\({}^{-1}\)). Therefore, only the samples taken from the exterior of the cave (POS22/01) and (more likely according to the interpretation of the spectrum) sample JAR22/01 can be considered comparable to the analyzed pottery. This, however, only shows up as a factor that can be highlighted for pottery that has a peak around 990 cm\({}^{-1}\) and a peak around 911 cm\({}^{-1}\). The analyzed pottery shows peaks typical of the component of aluminum silicates around lower values, such as 990 cm\({}^{-1}\), and it never shows values above 1000 cm\({}^{-1}\).