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Exploring Great Salt Lake one spot 13 different lines or rings of elevation of the water on the shore yesterday. (Water lines)." And Gunnison noted that "The Salt Lake Valley is one of those which one called `terraced'- . . . These terraces or benches appear to have been formed from the crumbling down of precipitous cliffs into water which once made this region a vast inland sea. "The successive subsidences of this ancient sea must have been in determinate portions and by sudden removals of portions of its barriers-""" A scientific appraisal of these earlier observations was not completed until the 1880s when Grover K. Gilbert named the ancient sea, Lake Bonneville, after Washington Irving's adven- turous captain, and then published the results of his investigations. He estimated the area covered by Lake Bonneville at its greatest extent to be 19,750 square miles, with a length from Cache Bay south to Escalante Bay of 346 miles, a width from the mouth of Spanish Fork Canyon to the Shoshone Range of 145 miles, a coastline of 2,550 miles, and a maximum depth of 1,050. These figures could be compared with the extent of the lake in 1869 which then had an area of 2,170 square miles, a length of 85 miles, a' width of 51 miles, and a maximum depth of 49 feet. To emphasize the size of Lake Bonneville, Gilbert indicated that if it were to rise again to its highest mark, the Mormon Temple in Salt Lake City would lie under 850 feet of water. Gilbert identified and named the three most conspicuous terraces: the Bonneville shore line at 1,000 feet above Salt Lake City (5,200 feet above the ocean) and an area of 19,750 square miles; the Provo shore line at 625 feet above Salt Lake City and with an area of 13,000 square miles; the Stansbury shore line at 330 feet above the city and an area of 7,000 square miles; and some intermediate shore lines between the Bonneville and Provo levels characterized by quite large embankments but without any sea- cliffs or terraces. It was Gilbert also who definitely determined that the outlet for Lake Bonneville was by way of Red Rock Pass in the northern end of Cache Valley and then along Marsh Creek and the Portneuf River to Snake River. The emptying of the lake reduced 25 Stansbury, Journal, vol. 3, 25 October; Gunnison, Journal, vol. 2, 22 December. 124 |
