THE RE ION OF MAMMALS. 205 



middle, the vestiges of brackish-water life ; and in the last 

 deposits, only relics of fresh waters mingled with washings 

 from the land. 



On the White River, in the Territory of Dakotah, in the 

 region where it approaches nearest to the Big Cheyenne, 

 are the Mauvaises Terres^ or Bad Lands, where Nature 

 seems to have collected together the relics of a geological 

 age, and buried them in one vast sepulchre. 



The country to the west and southwest of Fort Pierre, 

 for some hundreds of miles, is an elevated, gently undu 

 lating prairie, through which the streams have cut deep 

 gorges for their passage to the larger rivers. It is a vast 

 basin filled with the still horizontal and semi-indurated sed 

 iments of an inland sea. The wear of the weather has left 

 many deep scars on the face of the country, and the Bad 

 Lands present us with the mere ruins of a formation which 

 was once continuous. The whole country is treeless and 

 desolate. The soil beneath the feet of the traveler conceals 

 the bones of the numerous populations which enjoyed ex 

 istence in the earlier Tertiary epochs. The whole scene 

 has the air of the domain of death and solitude. On catch 

 ing a glimpse of the Bad Lands proper, a most impressive 

 exhibition presents itself. Here, in the surface of a vast 

 plain, is a sunken area thirty miles wide and ninety miles 

 long (Fig. 78). From the bottom of this sunken plain rise 

 domes, and pinnacles, and monuments, and massive walls, 

 which persuade the traveler that he is about to witness the 

 movements and listen to the hum of a vast city. In the 

 language of Dr. Evans an eminent geologist who almost 

 &quot; dwelt among the tombs&quot; of the ancient world, as they lie 

 stretched out from the Mississippi to the Pacific shores 

 &quot; these rocky piles, in their endless succession, assume the 

 appearance of massive artificial structures, decked out 

 with all the accessories of buttress and turret, arched 



