Report of U. S. National Museum, 1 899. Merrill. 



PLATE 17. 



Fig. 1. 



% * 



Fig. 2. 



MlCROSECTIONS SHOWING THE APPEARANCE OF (1) ALBANY COUNTY, WYOMING, 

 CLAY AND (2) FULLER'S EARTH. 



The enlargement is the same in both cases. 



