A great number of these were found in the mound. As regards their shape they fall into two classes, either finished implements or chips from the workshop. As regards the material of which they are made, they also fall into two large separate classes: those of the usual, light stone natural to the place such as flint, chert (in green or brown variety), horn-stone, jasper, etc., and those of obsidian (volcanic glass), which was not to be had in the immediate locality, although it was the preferred material. The classification according to material is the more important. There were found about twenty-five obsidian objects (among them a very few rough pieces or waste bits from the workshop, the latter all small) and about 140 hewn stones of other kinds of material. Most of these were waste from the workshop, all of the size of implements, but relatively few (about one-fourth) complete tools.
The obsidian implements came from the Ist to the IXth strata, but most of them were found in the upper layers. Nearly three-fourths of them were taken from the three upper strata. In stratum II alone there were ten implements and one piece of obsidian in the rough. It can certainly be inferred that the great quantity of obsidian tools from II was connected with the custom of burning the dead and of casting their belongings into the flames. In addition, the great number found here shows a broader and more universal use of obsidian in the making of implements.
They are all of very simple form, such as arrow-and spear-heads,[[114]] spear-like points and a flat knife-like blade, made from the rough stone by polishing off bits[[115]] (see [plate 10], figs. 11 to 16). Arrow-heads of obsidian were found only in stratum II, comp. 1-8676, [plate 10], fig. 13, the blade-like knife, 1-8633, fig. 11, and the spear-like knife end, 1-8634, fig. 16, which were found there. 1-8926 from stratum VIII, fig. 15, may have been either a spear-head or a knife. Fragment 1-8536 from stratum I, fig. 12, by virtue of its two unevenly arched surfaces, and 1-8883, fig. 14 of the plate, from stratum VIII (found nineteen feet down in the tunnel between parts 8 and 9 of the shaft frame) on account of its long peg-like lower end, may be parts of knife-like implements. They were fastened on rod-like shafts similar to the fine-handled knives of southern California shown by Professor Putnam and which are in an excellent state of preservation.
From a technical standpoint, it is worthy of note that implements of such perfect workmanship as figs. 12[[116]] and 13 were not found among the obsidian implements of the lower strata of the mound. A proportional decrease in obsidian implements of good workmanship can be noted as one approaches the lowest strata.
In northern California obsidian is found near Mt. Shasta, on the north side of Mt. St. Helena and in pieces to the size of an ostrich egg in Napa Valley.[[117]] It is a product of volcanic eruptions, phenomena which were of frequent occurrence during the tertiary period. The material of which the implements found about the bay in all the shellmounds were made must have come from one of the above-named sources through trading. The small number of such implements found in the shellmounds is probably the result of the comparative rarity of the obsidian in this locality and the resulting care with which it was hoarded.
It is to be inferred that at no period was obsidian exclusively the material used for chipped stone implements, since workshop waste composed of materials found in the neighborhood has been discovered up to stratum II. Since, however, waste and no finished implements of local materials have been found above stratum V, the instances of the use of such must have been relatively isolated in the upper strata. Toward the lower strata, from about the VIIth but practically from the VIIIth on, there is a great increase in workshop waste. Stratum V is the uppermost one out of which one or two single objects (among them 1-8756, [plate 6], fig. 21) may be considered finished implements. Of the thirty-nine implement-like objects obtained in excavating, only one is of unusual workmanship, an arrow-head of chert, 1-8815, [plate 6], fig. 19, which comes from stratum VII, at the lowest part of cut C. The extraordinary accumulation of objects of chipped stone which can be termed implements begins with stratum VIII and continues down to the lowest stratum X. A considerable number of these is shown in [plate 6]. It is, however, remarkable that of these not one shows in its workmanship complete mastery in the handling of the material. The implement which, though still crude, shows the next best workmanship is the leaf-like point of crystalline rock, 1-8929, [plate 6], fig. 20, from stratum VIII, found at the innermost end of the gallery.[[118]] All of the remaining implement-like objects of chipped stone bear the marks of crudity as do all of those that come from strata IX and X. It is very noticeable that because of this crudity in most of them, the line between implement and waste is very vague. It was therefore difficult to decide in the case of many objects whether they were to be regarded as tools at all. On the other hand, it is probable that a number of pieces included under rubbish may have really served as tools.[[119]]
Resulting from the discovery of obsidian, [plate 10], fig. 15, chipped stones of good workmanship were found as far down as the upper part of stratum VIII. It is extremely doubtful whether they appeared at all in the strata below this. The objects made of material from the vicinity of the mound were certainly made during its settlement. A characteristic mark of the uniform crudity of all of these tools made of local materials and found in the lower strata is that they all are worked from but one side and that the elaboration of that side is accomplished by but a very few strokes. The only exception to this is the point, from stratum VII, [pl. 6], fig. 19, which as to technique belongs in another place. [Pl. 6], fig. 18, 1-9012, shows a ridge-like elevation on its lower side, thus forming an unimportant and superficial exception. The point, 1-8929, [pl. 6], fig. 20, is also entirely even on its under side. In this they have a peculiarity characteristic of the well known “turtle-backs.”[[120]] This latter kind which in the eastern states of the United States has been found typical of the implements of the palaeolithic age is to be recognized in two objects in our collection, 1-9095, of green chert, [pl. 6], fig. 2, from stratum X, and 1-9007 of a crystalline substance, [pl. 6], fig. 1, from stratum IX. The first of these is without a doubt an implement, and the second is probably one. The palaeolithic turtle-backs of the East are unmistakably to be differentiated from the two objects under question in the material of which they are composed, which is argillite. In any case, however, the presence of these two objects proves that primordial species of stone implements existed into the neolithic period (for the mound rests on alluvial soil) and they may give ground for the establishing of the period from which such implements date, which is even farther back than that. The conical piece of jasper brought to a point by chipping, 1-8851, [pl. 6], fig. 3, from stratum VIIa, illustrates how implements were made by chipping from larger pieces of stone, and may even be itself a tool. It cannot be stated indisputably that the greater number of the common forms of chipped stones shown on [pl. 6] were obsolete among the latter inhabitants of the mound. But it must be noted that the greater number and the most characteristic of them do not appear in the upper strata. We may surmise that as far as they did occur among the founders of the upper strata they had a better form. In addition to the pointed ([pl. 6], figs. 19 to 20) and knife-like implements (fig. 21) the following important types are represented.
1. Long scrapers sharpened on one side, 1-9012, fig. 18, from stratum IX, and 1-9093, fig. 17, from stratum X.
2. Chisel-like tools terminating in front in a straight sharp edge, 1-8857, fig. 14, from stratum VIIa, and 1-9080, fig. 15, from stratum X.
3. Scrapers, more or less rounded off or oval, 1-9023, fig. 8, from stratum IX, 1-9053, fig. 9, from stratum IX, 1-9085, fig. 10, from stratum X.[[121]]