Twin Sisters

SINGEWALD, Q.D., 1951, GEOLOGY AND ORE DEPOSITS OF THE UPPER BLUE RIVER AREA, SUMMIT COUNTY, COLORADO: U.S. GEOLOGICAL SURVEY BULLETIN 970, 74 P.CONSV. DIV. COMP. DATE, 8,65WILSON, ANNA B., AND LAROCK, EDWARD J., 1991, ASCII DATABASE FOR PRINCIPAL LODE MINES AND MINEALIZED AREAS IN SOUTHERN SUMMIT COUNTY, COLORADO, U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 91-0027A AND B, 22 P. AND ONE DISKETTE.WILSON, ANNA B., AND LAROCK, EDWARD J., IN PRESS, MINERALIZED AREAS AND PRINCIPAL LODE MINES IN SOUTHERN SUMMIT COUNTY, COLORADO, U.S. GEOLOGICAL SURVEY MISCELLANEOUS FIELD STUDIES MAP MF-2163, SCALE 1:50,000.