Page:Walcott Cambrian Geology and Paleontology I.djvu/21

Rh .—From Mt. St. Piran, the type locality.

.—Mainly gray, quartzitic sandstones, with a few bands of siliceous shale.

.—At Mt. St. Piran, 2,640 feet.

.—Lower Cambrian in the upper portion.

.—On both sides of Lake Louise, at its upper end; well shown on the northwest and north sides of Fairview Mountain.

.—From Lake Louise, the type locality.

.—Siliceous shales.

.—At upper end of Lake Louise, 105 feet.

.—Lower Cambrian.

.—Northeast slope of Fairview Mountain.

.—From Fairview Mountain, the type locality.

.—Gray, quartzitic sandstones.

.—On east slope of Fairview Mountain, 1,000 + feet.

.—Unknown. No attempt was made to find fossils in this formation.

The section in Blacksmith Fork Canyon was first measured by Mr. F. B. Weeks, assisted by Mr. L. D. Burling, in a general reconnaissance of the northeastern and central parts of Utah made in 1905. In 1906 I established a permanent camp in the canyon and, assisted by Mr. L. D. Burling, spent nearly two months in detailed work upon the section and its faunas.

Near the close of the summer, camp was moved to Mill Canyon, in the Bear River Range, about 5 miles west of Liberty, Bear Lake County, Idaho, where Mr. R. S. Spence, of Evanston, Wyoming, had discovered a remarkable deposit of lower Middle Cambrian fossils. The section at this point was measured and found to agree quite closely with that in Blacksmith Fork; and the shale, which contained the rich fauna discovered by Mr. Spence, was called the Spence Shale horizon of the Ute formation from Spence Gulch, in which it has its great local development.