The physiography of the Rio Grande valley, New Mexico, in relation to Pueblo culture / by Edgar Lee Hewett, Junius Henderson, and Wilfred Robbins.

Edgar Lee Hewett

Date:: 1913

Credit: The physiography of the Rio Grande valley, New Mexico, in relation to Pueblo culture / by Edgar Lee Hewett, Junius Henderson, and Wilfred Robbins. Source: Wellcome Collection.

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$HENDERSON] ROBBINS J CLIMATE AND EVIDENCE OF CLIMATIC CHANGES 65 been observed for many years, particularly Great Salt Lake, which is known to have increased its depth 11 feet and its area 600 square miles from 1867 to 1871 -1 Indeed, the history of the landlocked lakes of the Southwest whose records have been found shows con- stant fluctuation during the last half century, rather than progres- sive change hi one direction; but any progressive change would be masked by the fluctuations and would be so slow that half a century is not sufficient to show it. The ancient embankments, bars, and other features of the old lake basins are so fresh as to indicate com- paratively recent retreat; and if, during a large part of the last 500 or 1,000 centuries, an infinitely slow change has been going on, as mdicated by the evidence, there is no reason to suppose that anything has happened to check the desiccation. At the present time the ratio of precipitation to dissipation is such in the West and the Southwest that glaciers can not exist where they were once abundant. One glacier 7 miles ]ong extended down to an altitude of 9,200 feet in the mountains near Santa Fe and several smaller ones existed there. Not far northward the San Juan and the Sangre de Cristo mountains and nearly the whole crest of the Conti- nental Divide in Colorado were all heavily glaciated. The literature of the subject is very voluminous, but only a few of the more impor- tant papers need to be cited.2 The high sierras in California and the Wasatch Mountains in Utah, together with the mountains of Oregon, Washington, Idaho, Montana, and northward, all had their systems of glaciers. Now no glaciers exist in New Mexico or Utah, only a few very small ones are found in Colorado,3 while the glaciers of Califor- nia, Montana, Wyoming, those of nearly the whole of North America, indeed, have shrunken much from their former dimensions. There is no way of knowing just when most of the shrinkage occurred, but the freshness of moraines and of glacial polish and stria on easily weathered surfaces has convinced nearly all observers that the glacieis of the southern Rockies were extensive at a very late period in the Glacial epoch and that the whole retreat has been geologically recent. This means some thousands of years for the greater part of St“7r0graPllS’ 0P-Cit': alS° P0WeU’J-W” ReP^onTands of the Arid JSecSalisbury, KoIIin D„ Glacial Work in the Western Mountains in 1901, in Joum. Geol ix ns-31 1J°1, Stone, George II., Remarks on the Glaciation of the Rocky Mountains Monoar TT 9 rJi c ’ **x,v,®W4, ** Slstanttol.C. E„ GMcMon in J. Joum Gcol.,xv, 15-22, 1907; Howe, Ernest, and Cross, Whitman, Glacial Phenomena of the Safjnan Mountains, Colorado, in Bull. Geol. Soc. Amer., xvn, 251-74, 1900* Hills R C Fvtinpt rio • r San Juan Mountains, Colorado, in Free. Colo. Set Soc 39^7883 A r T , \ 1 ° 391-96,1884. ’ ’ ’ 1883’ Amer- Journ. Set., 3d ser., xxvn, Will, TSt^pt’ GU g lr-> A Living Glacier on Hague’s Peak, Colorado, in Science x 153-54 iw Willis I., Phe Glacier of Mt. Arapahoe, Colorado, hi Joum. Geol vm 047-54 I'k’mi- Vfr ’ The Arapahoe Glacier in 1902, ibid., x, 839-51 1902- SiebenihJ r. Vv„, C, ’ Fenneman’ N- M.f 67519°—Bull. 54—13 o$