It is evident that the character of the objects in the upper strata is entirely different from that of the implements which are found in the lower beds. Well polished stone implements and obsidians diminish the nearer we come to the bottom. The sporadic occurrence of a well polished stone implement in the 8th stratum of the first column has an entirely abnormal aspect, in view of the otherwise complete absence of such objects from the VIth stratum downward. The abnormal increase of objects of the 1st and 2nd kinds in the IInd stratum is doubtless due to the custom of throwing their possessions into the fire during the cremation of the dead. Still, the IInd stratum yielded a sufficient number of fragments of similar objects which were evidently lost in other ways. So few are furnished by the contents of the lower strata that their limited use is apparently indicated. In fact, even the Vth stratum shares this poverty, for its four polished implements are only represented by fragments of metate-like stones and a tablet of slate, polished on one side. In the lower strata flaked stones (of local materials), bone splinters of an awl-like shape, and knife-like tools of bone predominate. Among the flaked stones, real implements are very numerous; they are missing in the upper strata. Their technique is primitive. On one side they are flat and are worked on the other side only. This working, too, is crude, and the finishing primitive. The turtle-back form is present. Different kinds of scraper-like tools of primitive form, and of drill-like sharpened stone fragments, must have been more common implements in the hands of the inhabitants of this stage than among the dwellers on the upper strata, where these tools are lacking.
A well formed implement of flaked stone, worked on both sides, was found low down in stratum VIII (a spear-like blade, [pl. 10], fig. 14). Strata IX and X offer nothing similar. The leaf-like blade from stratum VIII ([pl. 6], fig. 20), where a crude workmanship is paired with an attempt at more regular sharpening of the edges, does not favor the view that the inhabitants of the mound had been well versed from the beginning in the production of chipped implements.
Very remarkable is the occurrence together of crude splinters of bone, which show from long use their real value as tools, and the neat, almost elegant, knife-like implements. Among the latter we find the only ornamental fragment of a tool of bone obtained during the whole course of the excavation. The people who used the splinters of bone for their tools were not so primitive but that they possessed elegant objects of bone, and not so far advanced but that they were often satisfied with such primitive implements as common bone splinters. But both classes of these typical tools are markedly different from what the upper strata of the mound offer in the line of implements. Hence the people of the lower strata must have represented a somewhat different mental type or a different degree of mental training.
It seems advisable, from what we know, to separate the older inhabitants who had settled here and raised the foundations of the mound up to the middle part of the VIIIth stratum, from the later population of the grave period. They may have been neolithic, they may have been connected with the following generation by some common traits, although there is little evidence for this; but the two people certainly differed in cultural characteristics.
The race that commenced building in the middle of the 8th stratum was apparently less different from the population of the upper strata than from its predecessors. But differences can here, also, be discovered. The chipped tools of local materials still continue for some time (about to VIIa), and obsidian seems to have come to them as a rather rare material. Only a few bone implements from grave 8 are extant in this group of strata. Contrasted with the usage of the people of the upper strata is also the use of bone arrow blades, which the last inhabitants of the mound apparently did not possess. They had not yet departed from an extended employment of bone as a working material; a fact usually more characteristic of a primitive people than of one further advanced.
One observation should still be made in this connection. It is a striking fact that in the fifth stratum and its immediate proximity a number of objects appear, the likeness of which was not found elsewhere in the whole mound. They are:
(1) Fragments of metate-like stones, stratum V.
A long, dull, chisel-like tool of horn, from stratum V.
A tablet of slate polished on one side, stratum V.
(2) Pieces of antlers, truncated for use as tools, stratum V, and a knife-like implement, stratum V.