I have called these flakes a product of industry; while the material itself is of course a mineral, the fragments scattered about are undoubted products of skill. They are chips and splinters. There is neither lava nor obsidian cropping out in or about the valley,[182] but highly volcanic formations are abundantly found to the north, within fifty miles from Pecos, in the high Sierra de Mora; perhaps, also, nearer yet. At all events, the mineral has been brought to the pueblo and chipped there. The same is the case with the flint flakes, agates, jaspers, and moss-agates, with the difference, however, that, in the case of these, water has done a great part of the carrying, if not all; whereas the drift of the _arroyo_ contains no obsidian nor lava, except such as has clearly been washed into it from the ruins. Among the flakes there will be noticed several which may have been used for knives, whereas still others approximate to the arrow-head. A small perfect arrow-head was found and transmitted by me to the Institute,--the only one I met with on the premises.[183] The fact that several localities at Pecos are completely devoid of obsidian has already been mentioned. These are the oldest ruins. In the case of the ruins along the mesa and those south of the church, I can only speak of the surface; but where the corrugated pottery was found the whole section of the bluff was exposed for more than 100 m.--327 ft.,--and still not a trace of the mineral appeared, while flint, agate, and jasper were rather conspicuous.[184] This may be accidental, but it is certainly suspicious and suggestive.