GEOLOGICAL CHANGES. Ill 



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westward train came along, and we were again in 

 motion toward the home of the buffalo. 



Before we slept the Professor gave us the following 

 information : The vast plateau lying east of the Rocky 

 Mountains, and which we were now approaching, was 

 once covered by a series of great fresh-water lakes. 

 At an early period these must have been connected 

 with the sea, their waters then being quite salty, 

 as is abundantly demonstrated by the remains of 

 marine shells. During the time of the continental 

 elevation these lakes were raised above the sea level, 

 and their size very much diminished. Over the new 

 land thus created, and surrounding these beautiful 

 sheets of water, spread a vegetation at once so beau- 

 tiful and so rich in growth that earth has now abso 

 lutely nothing with which to compare it. Amid these 

 lovely pastures roved large herds of elephants, with 

 the mastodon, rhinoceros, horse, and elk, while the 

 streams and lakes abounded with fish. But the 

 drainage toward the distant ocean continued, the 

 water area diminished, the hot winds of the dry land 

 drank up what remained of the lakes, and, in process 

 of time, lo ! the great grass-covered plains that we 

 wander over delightedly to-day. What folly to sup- 

 pose that such a land, so peculiarly fitted for man's 

 enjoyment, should remain, through a long period of 

 time, tenanted simply by brutes, and be given up to 

 the human race only after its delightful character- 

 istics had been entirely removed. 



