37° W.. C. KNIGHT 



in America. A discussion of this subject cannot be taken up here, 

 but the following notes are worthy of consideration. Of the 

 forty-four genera of invertebrates known in the Kansas and 

 Nebraska rocks, over three fourths of them belong to the Permian 

 of the Orient. The remainder are nearly all American genera 

 and are chiefly pelecypods. In referring to the English Permian 

 it will be seen that there are reported thirty species of brachio- 

 pods and thirty-seven species of pelecypods, while in America, 

 with a fauna only partially known, there are fifteen brachiopods 

 and between forty and fifty species of pelecypods. Besides 

 this, there is the disappearance of the Spirifers, the most 

 of the Producti, and the most of the typical Coal Measure 

 species. 



Some have objected to the use of the term Permian to desig- 

 nate an American terrane. There seems to be no good reason 

 for this. In this country, as in Europe and India, there is a 

 series of rocks above the Coal Measures that cannot be con- 

 sistently classified with them. While they are linked with the 

 Paleozoic with unmistakable affinities, they are also bound to the 

 Mesozoic by indubitable bonds. Since the term Permian has 

 been in use many years to represent this formation, in this, as 

 well as foreign countries, it seems ill advised at this time to 

 introduce a new term to designate the American formations. 

 We might as consistently cast off other period names that have 

 had their origin in a foreign country. Since the Permian is a 

 typical transition series, it seems advisable to speak of it as a 

 geological period of the Paleozoic, and no longer consider it an 

 epoch of the Carboniferous. 



In order to show the close relationship of the American and 

 foreign Permian, a table has been arranged which will give all of 

 the genera known to the Kansas and Nebraska Permian, and also 

 show their distribution in the foreign Permian. The resemblance 

 is even greater than appears in the table, since it has been impos- 

 sible to secure accurate data relating to many of the foreign 

 genera. 



