356 C. S. PBOSSER 



that they may not be of Triassic age, but in all his later papers 

 upon the forms he refers to the beds as Permian. I suppose the 

 reason for this collocation is the fact that the nearest related 

 forms are found in the European Permian. Thus, Euchirosaurus 

 and Actinodon are referred to the lower Permian in France (the 

 Rothliegenden of Autun). I at first thought that the present 

 form might be Acti?wdon, but the bones made out agree quite 

 closely with the figures of Eryops megacephalus given by Cope." 1 

 The above brief summary of the Permian rocks of Kansas 

 shows that fossils occur in beds varying in thickness from iooo 

 to 1350 feet; while if all of the Red-beds are of the same gen- 

 eral age, as is possible, the estimated total thickness of the Per- 

 mian would then range from 2050 to 2650 feet. The majority 

 of the species found in the lower 400 feet, the Permo-Carbonif- 

 erous deposits, occur in the Upper Coal Measures (Missourian) , 

 and perhaps one half of the species in the succeeding 300 or 400 

 feet ; but above that horizon none have been found which are 

 even closely related to those in the Coal Measures. On the con- 

 trary, this higher fauna seems to be as nearly related to the Tri- 

 assic as to the Carboniferous. This would seem to be sufficient 

 proof that the greater part of Permian strata does not contain 

 "precisely the same fauna as our Missourian or Upper Coal 

 Measures," since only the lower 400 feet of deposits, ranging in 

 thickness from 1350 to perhaps 2650 feet, contain a fauna com- 

 posed largely of species which occur in the Upper Coal Meas- 

 ures. These lower beds are transitional, but this fact does not 

 seem to the writer to furnish sufficient proof that the higher 

 ones at least are not of Permian age. 



Charles S. Prosser. 

 Union College, 

 March 1899. 



1 Letter of Feb. 26, 1899. 



