336 



BEPOBT OF NATIONAL MUSEUM, 1899. 

 Analyses of adobe. 



The name loess is given to certain quaternary surface deposits 

 closely simulating adobe, but concerning the origin of which there is 

 considerable dispute. Deposits in the United States are, according to 

 the best authorities, of subaqueous origin. Clays of this nature are, 

 as a rule, higher in silica than the adobes and correspondingly poorer 

 in alumina. Loess is a common surface deposit throughout the Missis- 

 sippi Valley, and is in many instances of such consistency as to be 

 utilized for brickmaking. 



The analyses given below are from Professor Russell's paper: 



Analyses of the loess of the Mississippi Valley. 



a Contains H of organic matter, dried at 100 C. 



