USGS Science⌕ Search

Geology topics

Edwin Thor McKnight

Publications and source records attributed to Edwin Thor McKnight.

5 recordsLinked to original sources
USGS1974

Geology and ore deposits of the Rico District, Colorado

The Rico district is in the Dolores River valley at the east end of Dolores County in southwestern Colorado. Mining has been actively carried on in the district since 1879. In the early days, silver was the chief product and was mined largely from Newman Hill southeast of the town of Rico. After 1900, the base metals, particularly lead and zinc, mined in other parts of the district, became the major products, though silver remained an important byproduct. The production of the Rico district from 1879 to 1968 has been about 83,000 ounces gold, 14,500,000 ounces silver, 5,600 tons copper, 84,000 tons lead, and 83,000 tons zinc.

Colorado↗
USGS1962

Lead in the United States, exclusive of Alaska and Hawaii

The productive lead districts in the United States (exclusive of Alaska and Hawaii) are shown on the accompanying map. The map is at a scale of 1: 3,168,000, (50 miles to the inch). Only those districts known or believed to contain 1,000 short tons or more of lead are shown; individual deposits within districts are not represented.

Mineral Investigations Resource Map↗
USGS1962

Silver in the United States, exclusive of Alaska and Hawaii

The productive silver districts in the United States (exclusive of Alaska and Hawaii) are shown on the accompanying map. Only those districts known or believed to have contained 100,000 troy ounces or more silver are shown. Three size categories, based on production and estimated reserves, are distinguished and indicated by size of symbols: districts containing 100,000 to 5 million ounces, those containing 5 million to 50 million ounces, and those containing more than 50 million ounces. Symbols show the approximate centers of the districts. Some of the more prominent districts are identified by name on the map, and all are numbered to correspond to the index. Because a name established through common usage may not be the legal name of the mining district, several names are given in the index for some localities. The index, arranged alphabetically by States, includes a brief description of major geologic features for most districts. Both published and unpublished data were used, and at least one reference is given for each locality if reports on it have been published.

Mineral Investigations Resource Map↗
USGS1940

Geology of area between Green and Colorado rivers, Grand and San Juan Counties, Utah

The area described in this report comprises about 900 square miles of arid land lying between the Green and Colorado Rivers south of the Denver & Rio Grande Western Railroad and southwest of the Salt Valley anticline. The rocks that crop out or that have been encountered in wells drilled in the area are all sedimentary and range in age from Pennsylvanian to Upper Cretaceous. Mesozoic strata are especially well represented. Including rocks that have been cut by drilling, the maximum thickness of the stratigraphic section is about 2 miles.

Utah↗