T. F. Jamieson — Inland Seas of the Glacial Period. 195 



— until now only Great Salt Lake and two smaller lakes remain. 

 Translated into terms of climate, these changes imply that there were 

 two epochs of excessive moisture — or else of excessive cold — sepa- 

 rated by an interval of superlative dryness and preceded by a climatic 

 period comparable with the present. The first epoch of humidity 

 was by far the longer/ and the second, which caused the overflow of 

 the waters, the more intense " (Second Annual Report of the U.S. 

 Geological Survey, Washington, 1882, p. xvii). 



In the same region there are traces of another large lake, which 

 is described by Mr. Clarence King in vol. i. of his work on the 

 Geology of the 40th Parallel. He calls it Lake Lahontan, and it has 

 been made the subject of further investigation by Mr. I. C. Russell. 

 The progress of events as traced out by these geologists harmonizes 

 very closely with what has been found by Gilbert in regard to Lake 

 Bonneville, namely, two periods of high-water separated by an 

 interval of great dryness. Of these two periods of humidity the 

 first continued longest, but the second produced the greatest rise of 

 the lake. The supposed connection of these events with the Glacial 

 epoch is thus expressed by Mr. King : — 



" The Quaternary lakes of the Great Basin (L. Bonneville and L. 

 Lahontan) are of extreme importance in showing one thing — that 

 the two Glacial ages, whatever may have been their temperature 

 conditions, were in themselves each distinctly an age of moisture, 

 and that the Inter-Glacial period was one of intense dryness, equal 

 in aridity to the present epoch." " We are warranted in assuming 

 for the first age of humidity of the lake an enormously long con- 

 tinuance as compared with the second. The first long-continued 

 period of humidity is probably to be directly correlated with the 

 earliest and greatest glacier period and the second period of humidity 

 with, the later Reindeer Glacier Period" (Geology of the 40th 

 Parallel, vol. i. p. 524). 



From these quotations it will be seen that the American geologists 

 have arrived at the same result for the Great Salt Lake Basin as I 

 supposed would occur in the Aralo-Caspian region, namely, a great 

 rise of the waters coincident with the occurrence of a Glacial period. 



Gilbert thinks there have been only two great rises of the lake 

 waters : " There is abundant evidence," he says, " that each great 

 rise and fall recorded by the shore-lines of Lake Bonneville was 

 interrupted by intervals of reverse motion, the rising waters occa- 

 sionally hesitating and sinking for a time, and the falling water 

 occasionally oscillating upwards. It may be asserted with confidence, 

 however, that the history includes but two great waves. If the 

 water had many times, instead of twice only, risen to the upper 

 levels of its range, the tell-tale sediments could not have failed to 

 record the intervening subsidences." And he further says that if 

 the student '' correlates the second humid wave with the Reindeer 

 epoch of English geologists, he will be surprised to find that in 

 Utah the climate was more severe than during the first maximum, 

 although maintained for a shorter period " (Second Annual Report 

 of the U.S. Geol. Survey, p. 187). 



