In 1863, Whitney himself began studies in the Yosemite region.[12] He concluded that the Yosemite Valley resulted from a sinking of a local block of the earth’s crust. His assistant, King, recognized evidences of a glacier’s having passed through the valley, but Whitney, although he published this fact in his official report, later stoutly denied it. Whitney at first believed the domes to have risen up as great bubbles of fluid granite. Galen Clark, while not a trained geologist, was a careful observer and commanded considerable respect from the public. He believed that Yosemite Valley originated through the explosion of close-set domes of molten rock and that water action then cleared the gorge of debris and left it in its present form. King, although he was the first to observe glacier polish and moraines in the Yosemite Valley, did not attribute any great part of the excavation of the valley to the glacier. He regarded the Yosemite as a simple crack or rent in the crust of the earth. John Muir, who followed these early students, maintained that ice had accomplished nearly all the Yosemite sculpturing. H. W. Turner, on the other hand, found no reason to believe that anything other than stream action, influenced by the peculiar rock structure, had had an important role in the origin of the valley, although he recognized that it had been the pathway of a glacier. Joseph LeConte,[13] W. H. Brewer, M. G. Macomb,[14] George Davidson,[15] I. C. Russell,[16] George F. Becker, Willard D. Johnson, E. C. Andrews, Douglas W. Johnson, F. L. Ransome, J. N. LeConte, A. C. Lawson, Eliot Blackwelder, Ernst Cloos, John P. Buwalda, M. E. Beatty, and George D. Louderback have all studied the geology of the Yosemite Valley or the Yosemite region and have published the results of their work. The influences of the topography of the Sierra Nevada upon meteorological conditions were studied and reported upon by W. A. Glassford in the early ’nineties. Prior to 1913, however, no one had made a comprehensive study of the geology of the entire Yosemite region. Ideas regarding the origin of the valley and related features were still hazy. In 1913, at the instance of the Sierra Club, the U. S. Geological Survey sent out a party of scientists to begin a systematic and detailed investigation. These men were François E. Matthes and Frank C. Calkins. The former was to study especially the history of the development of the Yosemite Valley; the latter to study the different types of rock. In the years that have elapsed, Matthes has carried his investigations over the entire Yosemite region and into the areas to north and south. Thus he has worked out quite definitely, back to its beginning, the story of the origin of the Yosemite and of the other valleys of the same type in the Sierra Nevada. His conclusions, published by the government, have stood the test of criticism by other members of his profession.