Stas 
U7 
V3 | UNITED STATES GEOLOGICAL SURVEY 
CHARLES D. WALCOTT, DIRECTOR 
CHOLOG Y 
OF THE 
ASPEN MINING DISTRICT, COLORADO 
With ALTEAS 
BY 
JOSIAH EDWARD SPURR 
SAMUEL FRANKLIN EMMONS, GEOLOGIST IN CHARGE 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1898 
