340 C. R. KEYES 



The question bids fair to remain unsettled, until some data 

 more tangible and critical are obtained. The deposits of the 

 Triassic of this region were laid down nearly under the same 

 conditions as some of the so-called Permian, The beds appear 

 to have been formed without interruption of sedimentation in 

 enclosed basins. Vertebrate and plant remains are to be 

 expected to form the prevailing forms of life. They can- 

 not be very well compared with marine invertebrate faunas. 

 Such a comparison would, if attempted, prove unprofitable. 

 The clue must be evidently sought in physical criteria, and 

 in the stratigraphy of the region. Sufficient work in this 

 direction has not been done. The exact line of demarcation 

 between the two must therefore remain undetermined for the 

 present. 



While this question is brought up at this time with the full 

 knowledge that it has little bearing upon the main theme here 

 presented, it is alluded to for the express reason that the same 

 problem that has come up in connection with the deposits with 

 which we have been comparing the American so-called Permian, 

 has troubled the Russian geologists in their study of the original 

 Permian area. Their Tartaran "Red Beds " are as perplexing as 

 ours ; and the opinions as to age are equally divided. Several 

 writers, notably Karpinsky, Nikitin, and Tschernyschew are of 

 the opinion that these deposits were laid down in isolated 

 inclosed brackish water lakes, that continued to exist into the 

 Triassic period. On the other hand, another group of equally 

 shrewd observers, headed by Amalitzky, Schtukenberg, Netchaiev, 

 and Krotov, regard all of these beds as Paleozoic. For all prac- 

 tical purposes the views of the last mentioned workers appear 

 most reasonable. 



In this country, the conditions appear identical with the 

 Russian. Amalitzky's idea is equally applicable here, unless it 

 is shown that marked and widespread unconformaties exist near 

 or at the top of the American " Red Beds " and that the 

 undoubted Triassic can be thus clearly separated. 



