ARTICLE VI. 
CHEMICAL EXAMINATIONS OF SOILS AND INCRUSTATIONS. 
BY J. D.-.EASTER, PH. D. 
WASHINGTON, November 14, 1855. 
Sır: Enclosed I have the pleasure of transmitting to you the results of my examination of 
the specimens of rocks, soils, salts, &c., placed in my hands by you for analysis. I have limited 
myself, in regard to the character of the examination, chiefly by the schedule furnished me and 
your written instructions. The numbers are those attached to the labels, and are cited in the 
order of examination. 
I remain, very respectfully, yours, 
JOHN D. EASTER, 
WM. P. BLAKE, 
Geologist U. S. Pacific Railroad Survey. 
No. —. Limestone from the Tejon Pass. 
Contains a considerable quantity of silica. 
Carbonate of lime. 
Alumina, 
Oxide of iron. 
Magnesia, (little.) 
Phorphoric acid, (trace.) 
No. 146.— Rock from under Basalt, Fort Miller, San Joaquin River. 
Soluble in water ; chlorides of— 
Soluble in hydrochloric acid— 
Alumina. 
Oxide of iron ; 
Sulphate of lime, (trace.) 
Magnesia. 
Soda. 
Potash, (tracee) 
The residue consists of sand and clay. 
No. 153.—Dark Bituminous clay.—San Pedro. 
Heated in a tube closed at one end it emits a strong bituminous odor and gives a small subli- 
. mate of sulphur. Burns in the air to a redish-brown mass. 
