USGS PRO. PAPER 80 BY B.S. BUTLERPG 111-113, 144-160, 168-17USGS BULL. 1135-B BY A.V. HEYL PG. 33-34U.S. 10TH CENSUS PG. 465-470 (1880)UGMS SPECIAL STUDIES 9 BY B. STRINGHAM (1964)UGMS SPECIAL STUDIES 16 BY B. STRINGHAM (1967)ENGINEERING AND MINING JOURNAL NOV. 22, 1879 PG 376-378SALT LAKE MINING REVIEW SEPT. 30, 1917 PG. 23-24