106 LAKES OF NOilTH AMERICA. 



lakes, there may not be equally wonderful records awaiting the coming of 

 the patient inquirer. 



Pleistocene Lakes of the Great Basin. 



During the time of great climatic changes that witnessed the birth, 

 growth, and decadence of the great lakes of the Laurentian and Winnepeg 

 basins, described above, equally important fluctuations occurred in the 

 lakes' of the Arid region. Many of the valleys of Utah and Nevada, and 

 of adjacent areas both north and south, that are now parched and desert- 

 like throughout the year, were then flooded,, and in some instances filled 

 to the brim so as to overfloAv. All of the enclosed lakes west of the Kocky 

 mountains were then of greater size than at present and underwent marked 

 changes in sympathy Avith the advance and retreat of glaciers on neighbor- 

 ing mountains, and had their oscillations controlled by the same causes, 

 viz., variations in precipitation, evaporation, and temperature. 



Of these numerous water bodies there were two of broad extent which 

 may be taken as types of their class and will serve to give an epitome of 

 the history of their time. The two ancient lakes referred to are Bonne- 

 ville and Lahontan^ and are represented on the map forming Plate 19. 



Lake Bonneville was named by Gilbert in honor of Captain B. L. E. 

 Bonneville, U.S.A., who made a bold exploration into the wilds of the 

 Rocky mountains in 1833,* and was the first j^erson to gather reliable 

 information concerning the region formerly occupied by the great lake 

 now bearing his name. The reader will perhaps have an additional 

 interest in the following sketch, when he recalls the "Adventures of 

 Captain Bonneville," so graphically described by Washington Irving. 



Lake Lahontan first received definite recognition in the reports of the 

 40th Parallel survey under the direction of Clarence King, and was named 

 after Baron LaHontan, one of the early explorers of the Mississippi valley. 

 Why LaHontan's name should have been thus connected with a region 

 more than a thousand miles beyond his farthest camp, in preference to 

 the names of men who boldly crossed and recrossed the land referred to 

 when it was a trackless desert infested with roving bands of savages, I 

 must leave to others to explain. 



As shown on the accompanying map, Plate 19, Lake Bonneville occu- 

 pied the basin in which Great Salt lake now lies, on the east side of the 



1 Clarence King, U. S. Geol. Exploration of the 40tli Parallel. Vol. 1, 1878, pp. 490-529. 

 — G. K. Gilbert, "Lake Bonneville." U. S. Geol. Surv., Monograph No. 1, 1890. - I. C. 

 Russell, "Lake Lahontan." U. S. Geol. Surv.. Monograph No. 11, 1885. 



