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Show 60 western Utah Academy of Sciences, Arts and Letters United States, studying and giving lecture courses at sev including the University of Utah. eral western universities Davis will be remembered for introducing his "cycle of ero sion" concept of' a systematic evolution of landscapes in predictable successive stages, each with its appropriate assemblage of land forms. For the surface produced by "Powellian base-leveling" Davis proposed the term "peneplane." When Gilbert's block-fault hypothesis for the origin. of the Basin Ranges was first seriously challenged by Spurr in 1901, Davis stoutly defended Gilbert in a series of classic papers which included his now famous deductive analysis of the physiographic features that should characterize' fault blocks in successive stages of topographic youth, maturity, and old age under conditions of subaerial erosion in an arid climate. Davis described several ranges in western Utah and northern Nevada as representing in general certain of the postulated stages, implying that differences in the times of major fault movement accounted for the notably different physiographic stages shown by the various ranges. In appreciation of the work of the famous contributors to Great Basin geomorphology, Davis in his later writings and lec tures memorialized them by referring to the "King Mountains" of fold origin, later reduced to the "Powell Peneplain" which was widely covered by lava flows and finally broken up and lifted to form the present day "Gilbert fault-block mountains." Although there were many other workers in the pioneer pe riod of Utah geology, none achieved the prominence of the four above mentioned. It may truthfully be said that the foundation of Utah geology was laid by Powell, Gilbert, Dutton, and Davis. Today the investigative activities of the Geological Survey are distributed among four major branches-geologic, topographic, water resources, and conservation. Its work has not only been intimately connected with Utah's development in geology but it has likewise been similarly associated with the development of the State's water resources and the production of coal and other min erals on public lands. In fact. since its creation the Survey has grown in stature and increased in usefulness, but it has not grown old. One of its first field offices was established at Salt Lake City, and that office is now one of the principal offices in the West. Its personnel numbers 42 persons. From this office geologic work is being done in Utah and adjacent areas; scientific and technical supervision is exercised over mining and oil-and-gas-production operations under the mineral-leasing laws; stream gaging is done in cooperation with the States of Utah and Nevada; investiga- |
