148 SPARKS FROM A GEOLOGIST'S HAMMER. 



again from the sterile rocks, and leave the continent as 

 lean as before the " reign of ice.' 1 



In that western country, but farther north, in "W^o- 

 ming, Major Powell has discovered an enormous fault or 

 break through the rocks. On one side the ponderous 

 crust of the earth was uplifted 25,000 feet, more than 

 four miles. The reader may picture a vertical wall four 

 miles in height. He may imagine himself standing at its 

 base and looking upward. Its summit is dimmed by the 

 smoke of distance. Its summit is half the time immersed 

 in the clouds. He need not imagine such a cliff; it is 

 not there; it has been planed down; the leveling tendency 

 of nature would not tolerate such inequalities. Twenty- 

 five thousand feet of solid rocks have been moved away. 



These are examples of erosion on the existing conti- 

 nents. I could point to many others, to the dissolution 

 of the hills of Texas, and their distribution over the plains 

 nearer the Gulf-border; to the wearing away of the east- 

 ern coast of the United States ; to the isolated hills ris- 

 ing 800* feet along the valley of the Amazons, standing 

 as vestiges of an extensive formation, ^vhich, in times 

 geologically recent, has covered the valley ; to the enor- 

 mous erosion of the continental mass in the neighborhood 

 of the mouths of the Amazons and Para; to the evidence 

 that the North Sea has been dry land since Tertiary 

 time, and that the Thames was then a tributary of the 

 Rhine ; to the proof that the English channel has been 

 excavated since the advent of man in Europe ; to the 

 Chinese record of hydrographic changes in China, which 

 have shifted the positions of great cities hundreds of miles 

 in relation to the sea. 



But I must close the citation of these evidences of the 



