LETTER OF TRANSMITTAL. 
Department of the Interior, 
United States Geological Survey, 
Washington, D. C, February £7, 1900. 
Sir: I submit herewith the manuscript for a revised and enlarged 
edition of Bulletin No. 148, entitled Analyses of Rocks, etc. Dr. 
Hillebrand's portion of the former bulletin is so much extended, and 
represents so distinct a demand, that it will be presented by him as a 
separate bulletin. 
Very respectfully, F. W. Clarke, 
Chief Chemist. 
Hon. Charles D. Walcott, 
Director United States Geological Survey. 
