492 



REPORT OF NATIONAL MUSEUM, 1904. 



The entire Paleozoic system was thus divided into three natural 

 divisions, as follows: 



Serai I 



Upper Paleozoic .-JUmbral -Carboniferous 



I Vespertine J 



Ponent I Latter Devonian 



Vergent and Carbonifer- 



Cadent ous . 



Middle Paleozoic. 



Post-Meridian. 

 Meridian 



Pre-Meridian 



Scalent 



Surgent 



Levant 



.< Hder Devonian 



Silurian 



Lower Paleozoic 



[Matin; 

 . Aaron 



al rCambrian 



Primal 



Coal Measures. 

 JMiddle Carboniferous 

 I Lower ( 'arboniferous. 

 [Catskill. 



|Chemung and Portage. 

 JGrenesee, Hamilton, and Mar- 

 I cellos. 



(I'pper Helderberg. 

 [Oriskany. 



Lower Helderberg. 



Onondaga Salt Croup and Ni- 

 agara Limestone. 



Clinton. 



Medina. 



Trenton Limestone, Utica and 

 Hudson River slates. 



Black River, Chazy limestone, 

 and Calciferous sandstone. 



Potsdam. 



The .sediments making up these Paleozoic strata were, according to 

 his views, derived from a land area now occupied, by the Tertiary 

 seaboard plain and the waters of the Atlantic Ocean. This deposition 

 was preceded by a wide movement of depression, which began in the 

 south or southwest and permitted the waters of the Appalachian sea 

 to occupy what is now the upper half of the southern Atlantic slope. 

 There was, however, left above water to the southeast of the present 

 Atlantic plain, a large tract of continent or great chain of islands 

 which, with numerous fluctuations in their limits, remained as such 

 down to the close of the Carboniferous period. 



He considered it as "susceptible of demonstration that the various 

 coal basins, bituminous and anthracitic, of Pennsylvania, Maryland, 

 Ohio, Virginia, Kentucky, and Tennessee were originally united," 

 "the whole as one great formation." This is essentially the view held 

 to-day. The structure of the coal, as lie viewed it, rendered " it ap- 

 parent that no irregular dispersion of the vegetable matter by any 

 conceivable mode of drifting * * * could produce the phenomena 

 which they exhibit," and he could not conceive of "'any state of the 

 surface adapted to account for these appearances, but that in which 

 the margin of the sea was occupied by vast marine savannahs of some 

 peat-creating plant, growing half immersed on a perfectly horizontal 

 plain, and this fringed and interspersed with forests of trees, shedding 

 their leaves on the marsh." In this he agreed with Beaumont, though 

 his evidence was of different character. He further believed that the 

 coal material became finally engulfed through earthquake action, the 

 sea receding and then returning once more laden with detritus, carry- 

 ing everything before it and reaching far inland. Thus the entire 



