642 GEOLOGY. 



ing all this, it yet appears that the life of the period was greatly impov- 

 erished. A census made a few years ago gave the known animal species 

 of the Carboniferous period as 10,000, while those of the Permian period 

 were only 300, or three per cent. A census to-day would probably 

 improve the Permian ratio notably, but the contrast would still be 

 great. 



I. The Plant Life. 



Change in the flora. — The change of the vegetation from the Car- 

 boniferous to the Permian in America was rather marked, but not, 

 at the outset, radical. There was a progressive evolution as the period 

 advanced. Fontaine and White l have shown that in West Vir- 

 ginia and Pennsylvania the lowest beds referred to the Permian, with 

 a record of 107 species, contain 22 species found also in the Coal Meas- 

 ures below, and 28 found in the Permian of Europe. Of the 22 species 

 found in the Coal Measures, 16 are common to the Permian of Europe, 

 so that only 6 species which may be regarded as distinctive of the 

 Coal Measures rise into the base of the Permian, and, with one excep- 

 tion, all the Coal Measures' species had disappeared before the second 

 fossiliferous horizon of the Permian series is reached. This implies 

 that a rather profound change was in progress, but that it was not 

 altogether abrupt. In some portions of Europe the change seems 

 to have been somewhat more gradual, and in others, where uncon- 

 formity occurs, somewhat more abrupt. In Nova Scotia and Texas 

 the transition seems to have been gradual, rather than abrupt. Respect- 

 ing the change in the southern hemisphere, opinion must be held in 

 some reserve until final correlations are established; but if the glacial 

 bowlder beds be taken as marking the base of the Permian, a transi- 

 tion seems to have been in progress somewhat earlier, and to have 

 become profound as the natural result of the glacial invasions, which 

 were followed by a new flora. 



Only a small part of the total floral change of the Permian appears 

 in the American record, as now known; but the nature of the early 

 change is distinctly indicated. The Lepidodendron disappeared and 

 the Sigillaria became very rare. The Catamites were greatfy reduced 

 in importance, and Equisetites, their successors in line, appeared, while 



1 Second Geol. Surv. Penn., Permian Flora, 1880. 



