GEOLOGICAL SURVEY OF THE TEEEITOEIES. 319 



original positions. In many cases these banks or bluffs have retained 

 their original steepness, and have increased in elevation as the breaking 

 down of the rock encroached on higher land. In other cases the rain- 

 channels have cut in without removing the intervening rocks at once, 

 and formed deep gorges or canons, which sometimes extend to great 

 distances. They frequently communicate in every direction, forming 

 curious labyrinths, and when the intervening masses are cut away at 

 various levels, or left standing, like monuments, we have the character- 

 istic peculiarities of " bad lands," or mauvaises terres. 



In portions of KanSas tracts of this liind are scattered over the coun- 

 try along the margins of the river and creek valleys and ravines. The 

 ui^per stratum of the rock is a yellow chalk, the lower bluish, and the 

 brilliancy of the color increases the picturesque effect. From elevated 

 points the plains appear to be dotted with ruined villages and towns 

 whose avenues are lined with painted walls of fortifications, churches, 

 and towers, while side- alleys pass beneath natural- bridges or expand 

 into small pockets and caverns, smoothed by the action of the wind car- 

 rying hard mineral particles. But this is the least interesting of the 

 peculiarities presented by these rocks. On the level surfaces, denuded of 

 soil, lie huge oyster-like shells, some opened and others with both valves 

 together, like remnants of a half- finished meal of some titanic race, who 

 had been frightened from the board never to return. These shells are 

 not thickened like most of those of past periods, but contained an 

 animal which would have served as a meal for a large party of men. 

 One of them measured 26 inches across. 



If the explorer searches the bottoms of the rain- washes and ravines, 

 he will doubtless come upon the fragment of a tooth or, jaw, and will 

 generally find a line of such pieces leading to an elevated position on 

 the bank or bluff' where lies the skeleton of some monster of the ancient 

 sea. He may find the vertebral column running far into the limestone 

 that locks him in his last prison ; or a paddle extended on the slope, as 

 though entreating aid ; or a pair of jaws lined with horrid teeth, which 

 grin despair on enemies they are helpless to resist ; or he may find a 

 conic mound on whose apex glisten in the sun the bleached bones of one 

 whose last office has been to preserve from destruction the friendly soil 

 on which he reposed. Sometimes a i)ile of huge remains will be discov- 

 ered, which the dissolution of the rock has deposited on the lower 

 level, the force of rain and wash having been insufficient to carry them 

 away. 



But the reader inquires. What is the nature of these creatures thus left 

 stranded a thousand miles from either ocean *? How came they in the 

 limestones of Kansas, and were they denizens of land or sea ? It may 

 be replied that our knowledge of this chapter of ancient history is only 

 about five years old, and has been brought to light by geological explora- 

 tions set on foot by Dr. Turner, Professor Mudge, Professor Marsh, W. 

 E. Webb, and the writer. Careful examinations of the remains discov- 

 ered show that they are nearly all to be referred to the reptiles and fishes. 

 We find that they lived in the period called Cretaceous, at the time when 

 the chalk of England and the green-sand marl of New Jersey were being 

 deposited, and when many other huge reptiles and fishes peopled both 

 sea and land in those quarters of the globe. The twenty four species 

 of reptiles found in Kansas, up to the present time, varied from ten to 

 eighty feet in length, and represented six orders, the same that occur 

 in the other regions mentioned. Two only of the number were terres- 

 trial in their habits, and two were flyers ; the remainder were inhabit- 

 ants of the salt ocean. When they swam over what are now the plains, 



