‘ Newport, R. I., October 23, 1881. 
Sir: I have the honor to transmit herewith the manuscript of the text 
and illustrations of Prof. Roland D, Irving’s memoir on the Copper-Bearing 
Rocks of Lake Superior. 
Very respectfully, your obedient servant, 
RAPHAEL PUMPELLY, 
In charge of Division of Mining Geology. 
Hon. Criarence Kina, 
Director of the United States Geological Survey. 
