LETTER OF TRANSMITTAL 
Department of the Interior, 
United States Geological Survey, 
Washington, D. C, January 31, 1906. 
Sir: I have the honor to transmit herewith a series of papers by 
various hands for publication as a bulletin. They represent mineral- 
)gieal investigations incidental to geological researches and important 
o the progress of geology, and are here brought together for con- 
venience of reference. 
Very respectfully, G. F. Becker, 
Geologist in Charge Division of 
Chemical and Physical Research. 
Hon. Charles D. Walcott, 
Director United States Geological Survey. 
