90 
r.EOLOGY 
of Wahlenberg, and refers the name to a figure of Cameroceras trenlonense, evidently copied from Palce- 
ontology of Hew York, vol. i, pi. 56, fig. 4; a fossil very unlike the 0. communis in every respect. Still 
further, he cites it as common in New York, Pennsylvania, Canada, the Mingan Islands, on the coast 
of Labrador, and in Newfoundland, near the straits of Bello Isle. Now the form figured is a rare fossil, 
known only in a few specimens found in New York. 
The author cites Orthis lestudinaria and Verneuili. Dalm. , as « species of Brachiopods related to Spi- 
rifer, which are found equally in Europe and America. » If the author has been as careless of his lo- 
calities as he has been in his citations of authorities, wo can judge very well of his accuracy in this case. 
The 0. Verneuili is one of Eichwmld’s species, and the figure in Marcou’s book is copied directly, re- 
duced in size, from Murchison and de Verneuil’s Russia and the Ural Mountains, vol. ii, pi. 12, fig. 1; 
and is there cited from two localities in Bussia, viz., Reval and the island of Dago. This is the first in^ 
timalion of its having been found in America; and as no locality is given, we may bo permitted to dis- 
credit it altogether. Orthis testudinaria is an abundant species in Europe and America. 
On page 23, it is asserted that most of the blue limestone in the neighborhood of Cincinnati is of 
the Trgnton formation. This was believed ton years since. The author appears not to be aware of what 
has been published during the last three or four years, or he would not have made the mistake. 
On page 24, speaking of the Hudson river group and Utica slate, he says; « Fossils are rare in 
this division.)) Perhaps no portion of the palaeozoic rocks is more densely crowded with fossils than 
this group when in an unaltered condition. In central and north New A’ork, in « Upper Canada and 
Bay des Noquets,)) the two latter localities cited by our author, — the fossils are extremely abundant. 
While Mr. Marcou says the only fossils of those rocks are Graptolites and fragments of I'rilobites , it is 
shown in the Paleontology of New York that more than sixty species of fossils are restricted to these 
beds, and more than thirty others are common to this formation and the Trenton limestone. 
Under the term Ui)per Silurian our author includes numerous rooks and groups, and among them 
the Pentamerus limestone of Now A'ork. This rock was so named from its containing great numbers of 
Pentamerus galeatus, this being, with its associated shaly limestone, the only position of that fossil. Now 
our author makes the rock Silurian, (p. 25) and describes and figures the fossil as Devonian (p. 31). He 
asserts that it is « oommon to Upper Silurian and Devonian of Eiu'ope , and is in the same geological 
position in America, but on this side of the Atlantic, it is especially found in the Devonian division. )> 
Now this fossil is never found in any rocks of America included by' this or any other author under De- 
vonian; nor is it true that it occurs in the Devonian of Europe. Had our author read whad was pub- 
lished on the other side of the Atlantic as long ago as 1848, ho would have known this. 
The author cites Upper Silurian rocks as forming o the upper part of the Falls of the Mississi[)pi at 
Fort Snelling. )) The explorations of Dr. Owen and others have shown that the rock is the Trenton li- 
mestone ; and it is underlaid by a soft , shaly and fuooidal mass representing the Birdseye limestone ; 
and that this rests on a sandstone belonging to the lower formations. It will surprise the ardent collec- 
tors of Ohio to learn that they have upper Silurian rocks « in the environs of Cincinnati.))") 
We much incline to doubt whether Fremont, Stansbury, or Wi.slizenius have brought unequivocal 
Silurian rocks or fossils from « several points in the Rocky Mountains , » and we equally question whe- 
ther Pentamerus oblongus has been found in North Carolina and Minnesota. Lockport, N. A'., Chicago 
and Minnesota are given as localities of Facosites gothlandica, which is not known in either of these pla- 
ces. On page 28 , we learn for the first time that « the Upper Silurian in America often contains beds of 
rock salt. » The italicising is ours, the statement is the author’s. 
“) We know something of the rapid growth of western towns, hut we c.innot suppose that the environs of Cin- 
cinnati extend to forty or fifty miles. (N. B. — «One of the standard books on Geology is certainly the : Ge'ograpliie 
e Mineralogique des environs de Paris, by Cuvier and Brongniart , which comprehends a circuit of several lumdred miles; 
(land so I am justified in saying ((the environs of Cincinnati)) for forty miles; but only a glance at the Map is 
((needed to show clearly the meaning of my phrase». — J. Marcou.) 
