74 THE POPULAR SCIENCE MONTHLY 



indications of such complex Assuring and faulting, but reasoned in 

 rebuttal, that pressure from the mile high rock-masses above had so 

 united yielding materials, subsequently transported by erosion, that all 

 the traces of fracture had been lost. 



Professor Whitney was most positive in his idea that denudation had 

 but little affected the formation of the walls of the valley or its domes. 

 Had there been a considerable amount of erosion, its evidence would 

 have been piled up in masses of debris along the course of the Merced 

 Eiver. "No ordinary denudation moulded the domes," he declared. 

 Instead, he insisted that the Sierran domes of granite were fashioned in 

 a series of concentric layers while the igneous rocks were cooling. 



Associated with Professor Whitney was young Clarence King, who 

 later won fame as the chief of the United States Geological Survey. 

 King was the first to trace the courses of glaciers down into the Yose- 

 mite Valley. He called attention to the beautifully-polished surfaces 

 gleaming above the floor of the valley and pointed out four distinct 

 moraines, one between Half Dome and Washington Column, a medial 

 moraine between Tenaya Creek and the Merced Eiver, a third, linger- 

 ing in the gorge of the latter stream above the Happy Isles, while a 

 fourth forms an imposing barrier below the narrows where the Cathe- 

 dral Eocks approach El Capitan. Clarence King did not claim that ice 

 filled the Yosemite Valley, but he declared its maximum depth to have 

 been about 1,000 feet. 



When John Muir first explored the Sierras, some forty-five years 

 ago, he became imbued with the belief that the carving of the Yosemite 

 had been effected almost entirely by ice. His earliest contributions to 

 the literature of science and of the Sierras was a series of papers in 

 which he endeavored to show how a vast sheet of ice, forty or fifty miles 

 in width, cut across the crest of the range, quarrying for thousands of feet 

 doAvn through more friable formations ; or enveloping and sweeping 

 over the harder masses of granite, leaving striated and polished domes 

 in the wake of the congealed flood. Muir attached great significance 

 to the "hanging valleys," cut off abruptly by precipices, two and three 

 thousand feet sheer. To this glacialist, their only logical explanation 

 was that a great plow of ice, shod with sharp abrasives, had furrowed 

 the main valley below to untold depth. All the wealth of scenic 

 wonders for which the Yosemite region is so famous, he contended 

 had been chiseled by grinding glaciers. Tracing the tributaries of the 

 San Joaquin, Merced and Tuolumne Eivers to their fountains of per- 

 petual snow, he discovered, during the seventies, no less than sixty- 

 five surviving glaciers still busy at their lapidary labors. 



Professor Whitney at first credited the discoveries of Clarence King, 

 referring in his report of 1865 to the fact that "King and Gardner 

 obtained ample evidence of the former existence of a glacier in the 

 Yosemite Valley." But, five years later he reversed his decision, de- 



