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GUIDEBOOK OF THE WESTERX UNITED STATES. 



detail that is amazing to one unaccustomed to the effects of the erosion 

 of rocks in a semiarid region. What infinite pains Nature appar- 

 ently takes even in carving one of these commonplace hill slopes! 

 This carving is, indeed, a work of art comparable to that of the most 

 skillful sculptor. 



As the traveler goes westward he finds many shale ridges, which 

 form the divides between parallel stream valleys that head in the 

 Book Cliffs. These ridges have either flat tops or tops that slope 

 regularly away from the front of the cliffs. The tops of the ridges 

 stand from 80 to 100 feet above the general level of the plain and 

 doubtless represent the surface of a former plain that stood that dis- 

 tance above the present surface. When that plain existed the streams 



FicrRB 54. — Projecting point of the lower salients of the Book Cliffs. View looking east 



from Thompson, Utah. 



could not cut deeper into it, and so the land was reduced to a gentle 

 slope, but later the streams acquired greater cutting power and they 

 have succeeded in eroding away most of the old plain except where 

 it is best protected on the divides. What caused the increased cut- 

 ting power of the streams is a difficult question to answer. It may 

 have been an uplift of the country, or it may have been a change in 

 climate by which the volume of water carried by the streams was 

 greatly increased. 



After the train has passed through cuts made in two or three of 

 these shale ridges it reaches the village of Thompson, or, as it was 

 formerly called, Thompson's Springs, a name ap- 

 plied to it because 5 miles up the canyon that opens 

 at this place there are several springs which have 

 been of great value. In a dry country all settle- 

 ment except on the railroad depends on the pres- 

 ence of water, and in the early days Thompson's Springs were the 

 chief source of supply for those who were forced to make the trip 

 across this inhospitable country. "\ATien the railroad was built the 

 springs were equally valuable as a source of supply for the locomo- 



Thompson. 



Elevation 5,160 feet. 

 Population 84. 

 Denver 528 miles. 



