IOWA ACADEMY OF SCIENCES. 231 



looked upon, so far as indicating their simultaneous origin, only 

 as happy accidents. Instead of furnishing proofs of time 

 equivalency it suggests for similar faunas merely likeness of 

 conditions, irrespective of time. Such faunal facies are only 

 biologically representative. They are merely homotaxial. 



In lithological and faunal characters the rocks are so nearly 

 alike that it is difficult to fancy that in the Urals one is on the 

 opposite side of the earth from our Iowa and Kansas beds. 



Among the pertinent questions regarding the so- called Per- 

 mian in this country three are of special prominence. They 

 are: (1) Should the Permian be recognized in America? (2) If 

 so, what is the taxonomic rank? and (3) what are the upper and 

 lower limits of the terrane, so-called? Without going into 

 details of these questions it may be suggested: 



First.— That while we have in America a great succession of 

 deposits identical in all essential respects to the original Per- 

 mian of Russia, the two great basins merely had similar his- 

 tories that are not necessarily connected, and probably were 

 wholly independent of each other and unrelated; that the 

 Russian Permian constitutes a geological province by itself; 

 and that therefore the term Permian should not be used as a 

 technically exact term in connection with the Mississippi val- 

 ley deposits. 



Second. — That Permian as originally proposed applies to a 

 provincial series, and according to our usual standard, has at 

 best a taxonomic rank below that of system. Also, in view of 

 the possible elevation of its subdivisions to the rank of series 

 the term will have no position in the scheme of classification. 

 It will be, no doubt, eventually dropped altogether, the various 

 series belonging to the succession being made a part of the 

 Carboniferous system. In this country the same plan has 

 already been proposed. 



Third. — That, with the solution given to the second question, 

 it is unnecessary to attempt to locate the limits of the so-called 

 Permian in this country. The divisional lines of the series 

 comprising the beds of the typical American section in Kansas 

 are already well defined, with the possible exception of the 

 upper member. 



The data upon which these conclusions are based are given 

 at length in another place. 



