1870.] 413 [Wincliell. 



out parallel. The St. Peter's Sandstone, the Galena Limestone, the 

 Mountain Limestone, the Laramie Limestone, are all without distinct rep- 

 resentation at the east. The Medina Sandstone, the Oriskany Sandstone, 

 the Schoharie Grit, and the IMarcellus Shale, are without distinct repre- 

 sentation at the west. But it seems to me that, for the Marshall group, 

 we have' discovei-ed a probable representative in the Catskill group of New 

 York. The lithological and paleontological facts which favor this identi- 

 fication have already been pointed out. If this identification be correct, 

 it will appear that the Catskill group is not to be regarded as thinning 

 and partially disappearing, in central and western New York, in conse- 

 quence of an original lack of sediments, but in consequence of subsequent 

 denudation upon a scale of vast magnitude. 



But it may be pronounced a fatal objection to this method of paralell- 

 izing, that the Catskill is regarded by the New York geologists, and by 

 others, as the American representative of the Old Red Sandstone, which 

 is generally admitted to be Devonian. In reply to this, I offer two sug- 

 gestions. First, it is not the universal opinion of European geologists 

 that the Old Red Sandstone, as restricted to Scottish deposits along the 

 flanks of the Grampians, and upon the southern borders of the Moray 

 Firth, is properly classed with Devonian strata. The North Devon strata, 

 to which the term Old Red Sandstone has been extended, are thought by 

 some to hold a lower position. The Scottish Old Red Sandstone may be, 

 in part, at least, of Carboniferous age. Secondly, the identification of 

 the Catskill with the Old Red, rests upon the similarity of a few scales of 

 fishes, especially of a supposed Holoptychms. But fish remains are quite 

 abundant in the Marshall group, and some of them of types similar to 

 those of the Old Red. Dr. Newberry has described three species from 

 Illinois. Moreover, the Molluscous fauna presents numerous affiliations 

 with the fauna of the Old Red, as delineated in Murchison's Silurian Sys- 

 tem ; and this resemblance, in fact, was the first circumstance which 

 turned my attention to the equivalency proposed in this paper. Among 

 Marshall fossils which I have noted as having near analogues in the Old 

 Red of Scotland, are the following: 



Analogues. 

 Ctenodonta lowensis, W. & W. Cucultea antiqua. Sow. 



Isocardia ? Jenngs, Win. Goniophora cymbseformis, 



Murchisonia quadricincta. Win. Turritella obsoleta. 



Holopella mira, Win. " gregaria. 



Finally, it may be observed, that, whether the Catskill be synchronized 

 with the Old Red or not, it holds a position above all the typical Devonian 

 rocks of Europe and America. Professor Hall '-^^ long ago stated that 

 " after the change which takes place at the termination of the Hudson 

 River group, there is, perhaps, nowhere else in the Paleozoic series so 

 complete a change in the lithological and Paleozoic features of the strata 

 as at the termination of the Chemung group. Over a considerable extent 



"■ Amer. .Tour. Sci., [2] v. 367, Note. 

 A. P. S. — VOL. XI. — 24e 



