DESCTUPTIOl^ OF SPECIES. PP. Ill 



modify the life of the lower, the existence of this convul- 

 sion alone wonld be of weight in indicating a later age for 

 the higher formation. We need not have necessarily un- 

 conformity. 



Let us now turn to the table of species, and determine 

 the bearing of the evidence to be derived from it on the 

 question now before us. 



Considering first the identity of the species named in the 

 table, we see that out of 107 found in the Upper Barrens of 

 West Virginia, 22 occur in the C6al Measures proper, while 

 28 are found also in the Permian of Europe, according to 

 Goppert, Weiss, Schimper, Geinitz, Grand' Eury, Gutbier, 

 Heer and others. 



Of the 22 species which are common to the Upper Bar- 

 rens and to the Coal Measures below them, 16 are also 

 found in the European Permian, leaving 6 not hitherto 

 found in the Permian. Of these 6, one is given by Bun- 

 bury as occurring at Frostburg, Maryland. This is Pecop- 

 teris elliptica. Bunbury makes no distinction of horizons 

 at Frostburg, and as the Upper Barrens occur there, it is 

 almost certain that this si)ecies should be credited to them. 

 This leaves 5 species, viz : Sphenophyllum filiculmis, Neu- 

 ropteris hirsuta, N. fimbriata, Pecopteris notata, and Go- 

 niopteris arguta. Goniopteris arguta is found by Prof. 

 Lesquereux only in the flora of Illinois, which flora is pe- 

 culiar in possessing many Permian types. The presence of 

 Neuropteris hirsuta may be explained by the fact that it is 

 a long lived plant, enabled by vigor of growth and consti- 

 tution to pass above the horizon which it characterizes. 

 Pecopteris notata occui's in the Anthracite Coal Region of 

 Pennsylvania. The geological horizons are not yet fully 

 worked out there, but enough is known of the height of the 

 column of coal measures in the deepest parts of the basins 

 to make it almost certain that the horizon of the Waynes- 

 burg Coal occurs there. 



But even supposing that these 6 species should be 

 credited without qualification to the true coal measures, 

 the number of true coal measure species in the above list 

 would be surprisingly small. 



