PHILOSOPHICAL SOCIETY OF WASHINGTON. 105 



in America with tiie same general lithological characters and many 

 identical species in the respective members. But the Permian had 

 not been so satisfactorily established, in America. In Europe the 

 Permian is often wanting from its proper place, and its univer- 

 sality there has been regarded as generally doubtful. Until 

 1858 it was not supposed to exist, or at least it was not pretended 

 to have been discovered in America. In 1858 its existence was 

 announced almost simultaneously in Texas and in Kansas. A 

 little later Prof. I. O. White announced Permian plants from 

 West Virginia. These announcements were at first somewhat 

 eagerly co°ntested, but the discussion fell to the ground as profit- 

 less, with the general impression that the Permian had not been 

 established. The palseontological difficulties arise from the fact 

 already noted, that Russian Permian types are found in the 

 West in the middle and lower Carboniferous; and types which 

 are low in the series in Europe are found high in the series in 

 America, while many types are common to all parts of the sys- 

 tem. There are, however, certain forms which have always been 

 regarded as distinctly Permian. 



Recently Mr. Walcott has brought from southern Utah or 

 northern Arizona a series of fossils obtained from beds overlying 

 the Aubrey limestone (= middle Carboniferous or Coal measures). 

 The beds from which they came are locally named the Shinarump, 

 and have been doubtfully assigned to the Lower Trias, with a 

 reservation in favor of the possibility that they might be Per- 

 mian. These fossils are palasozoic, with the exception of one or 

 two forms which may be mesozoic. Among them is a species of 

 Bakewellia, which has never been found above the Permian; and 

 the group, as a whole, seems to indicate that the beds in question 

 belong decidedly to that age. Although this discovery would 

 make these beds and their equivalents throughout the West the 

 correlatives of the Permian of Europe, it does not follow that the 

 periods were strictly coeval in the two continents. 



Mr. Gilbert remarked upon the relations of these Permian 

 beds to the Aubrey limestone upon which they rest, and stated 

 that the contact was frequently, and perhaps generally, uncon- 

 formable in the vicinity of the locality where these fossils were 

 found. But no such unconformity had been detected in higher 

 horizons, and hence no physical break had enabled the separation 



