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



the ocean, owing to the great heat drying up the water. Now this 

 heat and dryness being much lessened during the Glacial period, 

 there must have resulted a much smaller evaporation, which would 

 no longer balance the inflow. These lakes, therefore, would swell 

 and rise in level, and thus the Caspian, the Aral, and the Balkash 

 might have spread until they became more or less connected into 

 a wide inland sea, discharging its surplus into the Euxine or along 

 that depression skirting the east flank of the Ural noticed by 

 Humboldt. This rise of the Caspian, damming back the waters of 

 the Volga and other streams, would occasion large deposits of 

 alluvial matter over the surrounding flat regions, and account for 

 many of the fresh-water beds that occur there. The other great 

 Asiatic depression to the north of the Kuenlun Mountains would 

 likewise be filled with water, and it is somewhat curious to find 

 that the Chinese have a tradition that Lake Lhop once drained into 

 the Hoang Ho. The sandy deserts of Central Asia are probably 

 the dried-up beds of these inland seas." 



Since the time this passage was written, many interesting facts 

 have been discovered which tend to support the opinion I have 

 there expressed. Some of these 1 now proceed to notice. 



The Great Salt Lahe Basin of North America. 



In the western dominions of the United States, between the Sierra 

 Nevada and the Eocky Mountains, there is a large extent of territory 

 with a very dry climate. Much of the surface is occupied by deserts, 

 and there are many salt lakes, of which the most notable is the Utah 

 Lake in the country of the Mormons. 



During the survey of this region by the geologists of the United 

 States evidence has been got that this lake had formerly attained a 

 much greater size, and must have been a sheet of water as large as 

 Lake Huron. The old shore- lines can still be traced with the 

 greatest distinctness along the hill-sides up to a height of more than 

 900 feet above the present level of the lake, and its whole extent has 

 been mapped out by Mr. G. K. Gilbert, one of the chiefs of the 

 Survey, who has made it the subject of special study. He has been 

 able to detect several phases in its history and has given it the name 

 of Lake Bonneville. It appears there have been two periods of high 

 water separated by an intervening dry period during which the lake 

 sank even below its present level, and in fact disappeared altogether. 

 Mr. Powell, Director of the Survey, sums up the history as follows : — 



" First, the waters were low, occupying, as Great Salt Lake now 

 does, only a limited portion of the bottom of the basin. Then they 

 gradually rose and spread, forming an inland sea nearly equalling 

 Lake Huron in extent, with a maximum depth of one thousand feet. 

 Then the waters fell and the lake not merely dwindled in size but 

 absolutely disappeared, leaving a plain even more desolate than the 

 Great Salt Lake desert to-day. Then they again rose, surpassing 

 even their former height, and eventually overflowed the basin at its 

 northern edge, sending a tributary stream to the Columbia River. 

 And, last, there was a tsecond recession, and the water shrunk away 



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