

wiluams.] J. w. DAWSON. 209 



to the true Coal Measures," with the exception that the Pernio Carbon- 

 iferous may be recognized in Bed C of Nebraska City. 



This practically closed the debate, although it did not solve the 

 Permian problem. The debate was ended, because the evidence was 

 perfectly clear that the rocks and fauna referred to the Permian, were 

 separable from those below by no stratigraphic or paleontologic break, 

 and petrographically only by differences such as are recognized in two 

 formations almost anywhere in the geologic series. The question 

 whether they be called "Permian" or "Coal Measures" would be set- 

 tled one way by those who considered it of chief importance to estab- 

 lish uniformity in the geological nomenclature of America and Kussia; 

 and it would be settled the other way by those who sought to establish 

 a natural classification of American rocks. 



The application of the name "Permian" to these rocks was purely 

 artificial, and as was stated several times during the debate, the class- 

 ification thus implied would not have been thought of if the rocks of 

 this region alone had been considered. 



The general question as to whether the Permian shall be ranked as 

 a system separate from the Carboniferous, is still an open one, and bids 

 fair to continue so until a natural method of classification for the time- 

 scale be devised, which shall be independent of the lithologic character 

 of the rocks. 



The correlation of the Permian in the Acadian and Appalachian 

 provinces is a distinct problem from that in the Mississippian province. 

 In the former plants enter into the question, and as I have previously 

 stated the correlative value of plants is not attempted in the present 

 essay. 



In chapter iv the Appalachian representatives of the Permian are 

 considered. 



The correlations of the Upper Carboniferous and Permian of the 

 Acadian province are discussed in Chapter xn, but a few words may 

 here be said regarding Dr. J. W. Dawson's correlations in the "Acadian 

 Geology," second edition, 1868. 



Dr. Dawson considered the Permian as absent in the Acadian district. 

 The Trias rests unconformably upon the Upper Carboniferous, and the 

 author held that the time represented by the Permian in Europe was 

 a period of disturbance in Acadia, with land extending over the greater 

 part of the region. 



The limestones of Colchester and Hants contain some fossils which 

 were regarded by Davidson as allied, if not identical with Permian 

 fossils 1 and Mr. Meek suggested that these may have constituted a 

 colony, in the Barrandian sense, of Permian forms in the Carbonifer- 

 ous age. The author, however, thought the deposits undoubtedly Car- 

 boniferous, and Lower Carboniferous, but that they assume some of the 



»— . _ — — 1 ■■>-: -"-■-■jv 



'Pp. 273-285, 



Bull. SO U 



