46 Parallelism of the Palceozoic Deposits 



If in Ohio, at the base of what is called the fine-grained or 

 Waverly sandstones, there exists some representation of the 

 Devonian beds, it is no longer so farther west. In the states 

 of Indiana, Kentucky and Tennessee, the Carboniferous sys- 

 tem comprises all the micaceous sandstones as far as the black 

 slates, their lower beds including true Carboniferous species, such 

 as the Spirifer striatus, Productus punctatus, &c* In Ten- 

 nessee a very abundant siliceous matter appears to have penetra- 

 ted the sandstones, and sometimes to have converted them into 

 chert, or a species of millstone (buhrstone) grit. These are the 

 siliceous strata of Prof. Troost, so important under an economical 

 point of view, from the quantity of iron which they contain. 

 These beds are sometimes filled with encrinites and corals, min- 



m 



gled with a small number of shells, characteristic of the Carbon- 

 iferous System. The psammites 



we thus unite with the Carboniferous system, are of great thick- 



ness, and cover a considerable extent of country, so that the 

 change which we propose will bring other important changes in 

 a map of the United States, colored according to the European 

 classification, such for example as that of Mr. Lyell.f 



* Mr. Hall, in his memoir upon the identity of the Western formations with 



those of New York, calls sub-carboniferous only the upper part of these psam- 

 mites. (a) 



(a) [I have not been so fortunate as to find fossils within two hundred feet above 

 the black slates, although they are abundant at a greater elevation. The lower por- 

 tion of these slates and sandstones in the vicinity of New Albany, la., have so 

 great a resemblance to the rocks of the Portage and Chemung groups, that I could 

 not forbear referring them to that period, while the more friable and micaceous 



sandstones above containing fossils of true carboniferous types, I called sub-carbon- 

 iferous, from the fact that up to that time I was not aware that anything below the 



base of the great carboniferous limestone had been recognized as belonging to the 

 carboniferous period. 



It will be recollected that there is a thickness of more than five hundred feet be- 

 tween the top of the black slates and the base of the limestone. — {Transactions 

 of Am. Association of Geologists and Naturalists, vol. i, p. 281.) This, if admit- 

 ted to belong entirely to the Carboniferous system, is an immense addition to its 

 thickness. On the other hand it must be recollected that this series holds the 

 place of the Portage and Chemung groups, which can be clearly traced into Ohio, 

 fitill holding a great thickness, and it seems scarcely possible that it can have en- 

 tirely disappeared in so short a space, while a subsequent deposit has extended to 

 Medina and Cuyahoga, in the eastern part of that state. 



Were this the proper orrasion, we might go on to show how* the Chemung group 

 of central and Western New York is more nearly relah id to the Carboniferous 

 sandstones of the West than to the Hamilton group of Eastern New York.— J- H.J 



t Our view has been adopted by Dr. Dale Owen, who has written to us, that since 

 our travels in these countries he has had an opportunity to verify the truth of it in 

 Kentucky, where he has recognized that in fact all the beds above the black sfate« 

 belong to the Carboniferous system. This slate furnishes then a very constant 

 horizon to distinguish the Carboniferous system from the lower deposits, (b) 



(b) [We have no disposition to find fault with the rpasoning of M. cle Vemeuil. 

 or with the facts which he brings to sustain his views, but a careful study of the 

 preceding pages clearly proves that no one point is yet established, and "that the 

 lioe of separation between the carboniferous and lower deposits is far from being 



