

vmb.] CLASSIFICATION OF THE CARBONIFEROUS, 77 



tion was made; bat Hall accepted it only after making a careful study 

 of the fossils for himself. To Hall the New York rocks were the stand- 

 ard. To de Verneuil, Sharp, and Lyell the English rocks were the 

 standard, and they had no prejudices in favor of any particular inter- 

 pretation of the American rocks. The lithologic characters were prom- 

 inent in Hall's correlation; to the English geologists, and particularly to 

 de Verneuil, fossils were the chief criteria. 



In the Carboniferous system the lack of a representative of the Car- 

 boniferous limestone in the Pennsylvania sections led to confusion, 

 in early reports we read of the Coal Measures as " secondary," and 

 of " transition coal-beds." (1835.) It was, doubtless, this supposition 

 that the true order was (1) limestone, (2) grit, (3) Coal Measures, that 

 led the Ohio geologists 1 to correlate the Corniferous limestone under- 

 lying the shales and fine grained sandstone (Waverly) with the Moun- 

 tain limestone. 



The Wernerian idea that anthracite coal belonged to the "grey- 

 wacke" or " transition," as taught in Couybeare and Phillips's geology 

 in 1822, and imitated elsewhere, 2 was the influencing cause of the 

 erroneous views as to the position of the eastern coal-beds of Pennsyl- 

 vania, as seen in the papers of James Pierce and William Meade, 3 and 

 others following up the discussion. In Tennessee the Mountain lime- 

 stone was rightly classified, because there the limestone was actually 

 next below the Coal Measures. 



A remarkable example of error arising from this firm belief in the 

 identity in the order of lithological deposits for America and England 

 is seen in the paper of Prof. C. Dewey, 4 who in 1838 interpreted the red 

 rocks about Kochester (Medina) as Old Red, and the overlying lime- 

 stones (Niagara) as ranking wtih the Mountain limestone of Europe. 



In the Mississippian province the identification of the rocks from the 

 Coal Measures downward was correctly made, not because of accurate 

 knowledge of the fossils, but because the three grand divisions of the 

 typical English Carboniferous system were there present in the same 

 order: first, a series of limestones, then conglomerate or sandstone, 

 then Coal Measures. 



Thus it came about that the true classification of the Carboniferous 

 was through the western or Mississippi Valley formations, and not 

 through the typical Appalachian sections in Pennsylvania and south- 

 ward, and their subdivision was made independently of the European 

 usage. The base was determined by the fossils of species allied to 

 the species of the Carboniferous limestone of England. 



In the Appalachian province the limit was determined by the top of 

 the marine Devonian rocks. But in the case of the upper limit, while 

 the general custom in America has been to regard the Coal Measures as 



»Ohio Geol. Survey, 2d Ann. Rop., by W.W. Mather, 1838. 

 •Geological Nomenclature, by Amos Eaton, 1828. 

 •See Am. Jour. Sci., 1st sor., 1827, vol. 12, pp.C9, 76, 

 •Am, Jour. Sci., vol. 33, p. 121. 



