The Salton Sea A Study Of The Geography The Geology The Floristics And The Ecology Of A Desert Basin

Author : D. T. Macdougal
Publisher :
ISBN 13 : 9781331949893
Total Pages : 266 pages
Book Rating : 4.9/5 (498 download)

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Download or read book The Salton Sea written by D. T. Macdougal and published by . This book was released on 2015-07-21 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from The Salton Sea: A Study of the Geography, the Geology, the Floristics, and the Ecology of a Desert Basin The geological and biological processes of the surface layers of the earth's crust are profoundly different under subaerial exposures to those which prevail under subaqueous conditions. Any region, therefore, which may be subjected to submergence and to weathering, alternately, will offer a changing complex of environic conditions, with accompanying disturbances in the balance and distributional movements of the organisms of the region. The solid ground, in one case, is subject to the erosion of precipitation-water and stream-flow, coupled with a leaching action of the water, while surface material will be variously transported and deposited. Wind effects will vary widely with aridity and other climatic features, while precipitation, evaporation, and temperature will act as determinants as to the character of the living forms supported. The submersion of any area may be expected to be followed by the complete or nearly complete destruction of the land flora and fauna. The temperature of the substratum is equalized, variations in moisture disappear, wind comes in only as an agency for transporting propogative bodies and as a cause of wave-action, sorting, wearing, and depositing material along shore lines. The deposition of sedimentary material in submerged areas under lakes takes place in such manner as to be easily distinguishable from the effects of stream-action. The superposition of the two groups of effects in any region such as the lowermost part of a desert basin, especially when submergence and desiccation alternate at intervals of sufficient length to give full force to the two extremes, might be expected to offer highly unusual physical conditions of the surface layers and of the soil, to which organisms would be expected to display reactions of interest and importance useful in the interpretation of phytogeographical phenomena in general. The great Cahuilla Basin, which lies to the westward of the lower or southern part of the main delta of the Colorado River, has been the scene of alternations of the kind in question. The lower part of this basin has been submerged and desiccated many times in the last few hundred years, as attested by the numerous beach or strand formations and layers of travertine on the shores. The making of the lake in 1904, 1905, and 1906, at the time of the organization of the work of the Desert Laboratory, offered opportunities for some studies the results of which are presented in the present paper. The facts to be taken into account were so diverse in character, and the necessary methods of calibration and estimation so unlike, that the cooperation of a number of workers in various branches of science was enlisted. First of all the senior contributor was so fortunate as to secure a general sketch of the geology and topography of the basin by the late Professor William Phipps Blake, whose barometric measurements as a member of the Williamson expedition in 1853 first established the fact that the region was an inclosed basin, the lowermost part of which was below sea-level. The history of earlier travel and the general geography of the basin is described by Mr. G. Sykes, geographer of the Desert Laboratory. The analyses of water samples have been carried out under the direction of Professor R. H. Forbes, at the Agricultural Experiment Station of Arizona, by the aid of Dr. W. H. Ross and Professor A. E. Vinson. The surface geology, with especial reference to the soil formations, has been the subject of much painstaking examination by Mr. E. E. Free, formerly of the United States Bureau of Soils. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com