598 THE GLACIAL LAKE AGASSIZ. 



Russell, appear to have entirely dried up Pyramid, Winuemucca, and other 

 lakes of Nevada about three hundred years ago.' On the other hand, the 

 high stage of Devils Lake before mentioned was near the time of the highest 

 known flood of the Red River, in 1826, when its water rose 5 feet above 

 the surface where Winnipeg is now built. Likewise it should be noted 

 that the highest known stage of the Laurentian lakes was in 1838, when 

 Lake Erie stood G feet above its lowest recorded stage, which was in the 

 winter of 1819-20. 



TEMPERATURE. 



Owing to the geographic position of the basin of Lake Agassiz, in the 

 central part of a large continent and nearly equidistant between the equator 

 and the north pole, the difference between the mean temperatures of sum- 

 mer and winter is great, the winters V)eing very cold and usuall}- some 

 portions of the summers very hot. The temperature, however, is mostly 

 cool and invigorating through the six or seven months in which the land is 

 worked and its harvest gathered. 



In summer there are commonly only a few excessively hot days (80° 

 to 100° F.) in a single heated term, which is preceded and followed by 

 longer terms of agreeable coolness, even at midday. It is also important 

 to note that, however hot the days may be, the nights, almost without 

 exception, through the whole summer are cool and favoi'able for refresliing 

 sleep. 



In winter, though the temperature is continuously below zero of the 

 Fahrenheit scale, even at midday, while the sun shines l^rightly, during days 

 and occasionally weeks together, the dryness of the air makes the extreme 

 cold (10° to 40° below zero) no more difficult to endure than a temperature 

 25° to 50° higher with the moist air of the region about the Lain-entian lakes 

 and on the Atlantic coast. Usually there is no considerable thawing at 

 any time during two or three n:ionths of the winter. Tlie ordinarily scanty 

 snowfall, which gives a sheet of snow seldom exceeding a foot in average 

 depth, is likely to serve well, if not too much drifted by gales at the time 



'Geological History of Lake Lahontau, U. S. Geol. Survey, Monograph XI, pp. 223-237, 252. 

 Compare G. K. Gilbert's Lake Bonneville, Monograph I, p. 258. 



