The Tolovana district is between lat 65°20' and 65°45' N. and long 147°50' and 149°00' W. in the upper drainage of the Tolovana River, a tributary of the Tanana. Brooks (1916, p. 201) reported that placer gold had been found in this area as early as 1892 but that no interest was aroused until 1914, when placers along Livengood Creek were discovered. Mining began in 1915 and was substantially increased the following year with the development of the deposits on .Livengood Creek and others on Gertrude, Ruth, Lillian, and Olive Creeks (Mertie, 1918, p. 256). The district continued to prosper and it was still productive on a small scale in 1959. Total gold production through 1959 was 375,000 ounces, all from placers. The bedrock in the Tolovana district is distributed in several bands or belts that cross the area in a northeasterly direction. The oldest rocks in the district crop out in the southeast ; the rocks become successively younger in a northwesterly direction. Briefly, the bedrock units consist of the Tatalina Group, of Cambrian or Precambrian age, Devonian and Silurian ( ?) sedimentary and igneous rocks, a chert unit of Devonian or Carboniferous age, and Carboniferous arenaceous and argillaceous units (Mertie, 1918, p. 230-256). Igneous rocks, chiefly basic, occupy a considerable area in the northwestern part of the district. Small bodies of granitic intrusives are scattered throughout most of the district. In the stream valleys, unconsolidated deposits of sand and gravel were deposited during several stages in the Quaternary geomorphic cycle. The earlier of these are only remnants and are seen as benches along the valley walls (Mertie, 1918, p. 230-231). Gold placers in the district are in bench and stream deposits (Mertie, 1918, p. 259). The bench deposits have been the more productive. The gold in the placers of Tolovana was derived from lowgrade lode deposits at the heads of many of the tributary streams (Mertie, 1918, p. 274-275).