62 



BUREAU OF AMERICAN ETHNOLOGY 



[bull. 52 



glass was colorless, with a refractive index about 1.510; occasionally 

 brown-colored glass fragments with refractive index about 1.53 were 

 observed. 



44.02 



31.77 



9.49 



85.28 



8.79 



99.51 



Class 



Order 



Rang 



Ratios 



Sal 

 Fem' 



85.28 7 

 8.79^1 



Q 44.02 5 3 

 F 31.77*^3^5 



K,0'+Na,0' .051 5 7 



CaO' 



.015 ^3*^1 



Subrang 



K,0' .024 5 3 

 Na^O' ".027*^3^5 



I. Tierra cocida, Alvear. J. G. 

 Geological Survey, analyst. 

 la. Molecular proportions of I. 



Fairchild, United States 



This analysis is similar to that of the loess 263717 from the same 

 locality. The relations of the several elements are not greatly 

 different, and the calculation of the analysis on the assumption that 

 it was made from a fresh eruptive rock leads to the same subrang 

 Tehamose of class 1 of the quantitative classification. 



The last three specimens, Nos. 263717, 263718, 263729, are evi- 

 dently modifications of the same material. This is indicated by (1) 

 their mineral composition, which was found to be ])ractically identi- 

 cal under the microscope except for the reddening of the argillaceous 



