CARBONIFEROUS AGE. 171 



table and animal life partook of the change and the whole move- 

 ment inaugurated or constituted 



THE PERMIAN AGE. 



This age was the last volume in the history of Palaeozoic life. 

 The great Appalachian revolution was only partially completed, 

 for the upward movement still continued. The peculiarities of the 

 coal age had ceased, but its impress was left on Permian times. 

 While the upward movement was advancing towards completion, 

 at many places, especially in Europe and Asia, around the borders 

 of the old coal fields, depressions still exi.-ted for extensive seas 

 which received the sediments that entombed and preserved the or- 

 ganic remains of the age. Hence we have records of the earlier 

 part of the age, but none of its latter portion, because the conti- 

 nents reached such an elevation that all the seas were drained, and 

 no place was left to stow away the debris and worn out life of the 

 period. The process of uplifting, therefore, was continued until 

 the continent was raised far above its present level, during which 

 none of its memorials could be preserved. The whole latter por- 

 tion, therefore, of the Permian, a portion of time incalculably long, 

 is a lost interval in geological history. For the first time in geo- 

 logical history the conditions were favorable for the complete 

 drainage of the continent. Lofty mountains produced great rivers 

 and steep inclinations towards the sea. Clear skies, took the place of 

 murky ones in the previous age. The seasons gradually became 

 more changeable and varied. The old vegetable and animal life 

 was not adapted to these conditions and hence it had. to change or 

 perish. As a matter of fact during this last interval occurred those 

 mighty changes in the fauna and flora of the globe which trans- 

 formed the Palaeozoic life into the middle or Mesozoic world. 



In the United States the Permian deposits occur mainly in Kan- 

 sas and Nebraska. Here the western boundary of the Permian 

 passes a little west of south, a few miles east of Lincoln, extending 

 to Beatrice, and thence into Kansas. Opposite Lincoln it is only a 

 few miles broad, but widens going southwest and through Kansas. 

 Towards the west at Lincoln and Beatrice it passes under the 

 Dakota group of the cretaceous. It is, however, as already inti- 

 mated, only the lower Permian that is here represented. In the 

 earlier Permian this portion of the continent was not raised above 

 the old carboniferous seas, and of course it received the sediments 

 brought down by the rivers and creeks from lands sloping towards 



