728 CHARLES S. PROSSER 



Cummins has correctly correlated the Fort Riley limestone with 

 the Texas deposits it furnishes a strong argument in favor of 

 referring the Upper Paleozoic formations of Kansas to the 

 Permian. 



Furthermore, the number of American geologists who believe 

 that these Upper Paleozoic formations should be correlated with 

 the Permian and given the rank of a period or system is probably 

 still smaller than the number of those who would retain the name 

 Permian but classify it as the upper series of the Carboniferous. 

 The writer had hoped to carefully study the fossils of these 

 formations and to present their complete evidence regarding 

 these questions, but other duties have prevented the execution of 

 this plan. It has appeared to me, however, that the weight of 

 evidence favored correlating the upper formations with the 

 Permian. 



Whether the Permian should be assigned the rank of a sys- 

 tem coordinate with the Carboniferous or regarded as the upper 

 subdivision of it is not quite clear, and the line of division 

 between the Permian and the Carboniferous is in doubt, as indi- 

 cated on the chart p. 730. The opinions of some of the lead- 

 ing European students of the Upper Paleozoic, who regard the 

 Permian as a distinct system and correlate certain American 

 formations with it, has seemed to the writer sufficient authority 

 for provisionally regarding it as a system, which was done in 

 the table of classification opp. p. 704 . It is probable> however, that 

 the U. S. Geological Survey will retain the name Permian, but 

 will classify it as the last series of the Carboniferous system. 



Conclusions of Dr. Keyes. — No one has, perhaps, insisted as 

 strenuously as Dr. C. R. Keyes that the name Permian should 

 be dropped from American geology. In 1897 he attended the 

 sessions of the International Congress of Geologists at St. Peters- 

 burg and participated in the excursions to the Carboniferous 

 and typical Permian of Russia. Later he prepared a paper on 

 the "American homotaxial equivalents of the original Permian," 

 and quotations from this cannot be regarded as from one favor- 

 ing the retention of the name "Permian." Regarding the litho- 

 logic features Dr. Keyes said : 



