DESCRIPTION OF SPECIES. PP. 119 



in the higher portions of Upper Barrens, and from the ex- 

 tremely small amount of it found in the lower portions, is 

 of more value, as indicating a great change from the con- 

 ditions which prevailed during the Carboniferous proper. 

 The beds of coal gradually disappear as we pass upwards, 

 and with the exception of the Washington Coal, are never 

 more than one or two feet thick, while the uppermost 200 

 or 300 feet contain none at all. This diminution of the coal 

 is accompanied with a great loss in the amount of plant 

 life. Only about 20 p. c. of the forms existing below the 

 Waynesburg Sandstone pass above it, and of these, many 

 are sparingly represented, and seem to be in process of ex- 

 tinction. These features are represented to be character- 

 istic of the European Permian. Grand' Eury, in his Fl. 

 Car. du Dej). de la Loire et du Centre de la France," 

 states that he finds the Permian to be marked by a diminu- 

 tion of coal, and a decadence of the flora. This is ^vhat we 

 w^ould expect a priori., if we should regard the Permian, 

 not as a distinct formation, but as the close of the Carbon- 

 iferous. The idea of its distinctness arose from the fact 

 that the Permian w^as first studied in Saxony and other 

 countries where a complete physical break exists, and 

 where the evidence of gradual passage could not be derived 

 from the stratigraphy and fossils. More extended study 

 of the formation in such countries as France show's that 

 this break is not universal, and that the passage from the 

 Carboniferous proper to the Permian is a gradual one. 

 The investigations of Weiss, Grand' Eury, and others, indi- 

 cate that the Permian is merely the closing period of the 

 Carboniferous. 



In the United States, there is no unconformity in the 

 strata from the lowest beds of the Carboniferous to the 

 highest stratum found in the Appalachian Coal Field. In 

 view^ of this, it is remarkable that we should find such 

 great changes in the flora as we actually do discover. 



To sum up finally tlie evidence derived from all sources, 

 we find ourselves irresistibly impelled to the conclusion, 

 that the age of the Upper Barrens of the Api)nlachiaa 

 Coal Field are of Permian age, by a consideration of : 



