Frederic William Galbraith
Ore minerals of the La Plata Mountains, Colorado, compared with other telluride districts
Economic Geology and the Bulletin of the Society of Economic Geologists (May 1941), 36(3):324-334

Abstract:
A recently completed study of about one hundred polished sections of ores from the La Plata Mountains in southwestern Colorado has revealed that certain paragenetic relationships between the sulphides and associated tellurides exist throughout the district. Because of the comparative scarcity of detailed information on the mineralogy of telluride ores it seemed advisable to determine if similar relations exist in other districts where tellurides are abundant. Accordingly, twenty-five sections of ores from Kirkland Lake and Porcupine, Ontario, and twelve sections from Cripple Creek, Colorado, were also examined. Although the number of sections from the latter camps is insufficient to establish the sequence of mineralization definitely for each of these districts as a whole, the relations observed are essentially identical with those exhibited by the La Plata ores.