426 AURIFEROUS GRAVEL MAN IN CALIFORNIA. 



where (Pis. Ill to XI), we inquire more full}- into their character 

 and appearance. Whitney has said that the gravels were deposited ])y 

 streams having violent currents, that the bones of animals were torn 

 asunder and scattered, and that all objects were necessaril}' more or 

 less worn; but it is observed that not one of the art objects attributed 

 to the gravels shows the least sign of rough usage or wear; the marks 

 they displa}^ of the tools employed in their manufacture or of the imple- 

 ments associated with them in use are as fresh as in the implements 

 and utensils found on modern Indian sites. This fact is so significant 

 that it can not be passed over without reasonable consideration. 



Glancing again at the numerous implements, utensils, and ornaments 

 attributed to the auriferous gravels, we may inquire. What materials 

 are represented? There are several varieties of stone, including 

 granite, andesite, rhyolite, slate, obsidian, etc. Andesite, however, 

 prevails, and at least one-half of the objects are of this material. As 

 most of these rocks in their original distribution are confined to some- 

 what limited portions of the geological column, some early and others 

 late, it is proposed to inquire whether any of the specimens are of 

 materials later in origin than the strata in which they are said to have 

 been found. Full data are not yet at hand for a satisfactory discus- 

 sion of this point; but it may be mentioned that andesite specimens are 

 reported from horizons extending all the way from the earliest to the 

 most recent gravels, yet so far as our geologists have gone this rock is 

 not found in the formations of the particular region until toward the 

 latter half of the Neocene. The objects being generally large, it is not 

 to be supposed for a moment that the}' could have been brought from 

 a distance. Again, obsidian is known only as a late product, having 

 its origin in the most recent flows of the Sierra, yet we have o])sidian 

 implements reported from the gravels of various districts, and in one 

 case, at least, from deposits that must belong very near the initial stages 

 of eruptive activity. This interesting line of research remains to he 

 followed up until definite results are reached; this, however, can not 

 be profitably done until the geology of the region is more exhaustively, 

 studied. 



The various objects attributed to the gravels b}' V03' and others and 

 now preserved in the nuiseum of the University of California were 

 examined at my request by Mr. F. L. Ransome, of the United States 

 Geological Survey, for the purpose of determining the material. The 

 result is, of course, only tentative, but Mr. Ransome is thoroughly 

 familiar with the formations of the auriferous region, and his determi- 

 nations are as satisfactory as can be made without cutting the speci- 

 mens and making slides for microscopic examination. The list furnished 

 is as follows: 



1. Lobed mortar. Fine-grained mica hornblende diorite; probably dyke. 



2. Mortar and jiestle. Mortar, diorite. A common peripheral facies of granodiorite 



wlien occurring in intrusive masses in foothills of the Sierra. I'estle is nut so 

 clear, but is apparently a fine-grained dioritic dyke rock. 



