Marcou’s Geological Map. 201 
_ The writer appears to be ignorant of what Dr. Owen has dis- 
covered in these strata on the upper Mississippi, viz.: Trilobites, 
Corals, Crinoids, Orthis, Lingula, etc. The Lingule are in a 
most perfect state of preservation ; and in numbers of individuals 
unsurpassed in any formation of any period. The author speaks 
of Barrande’s labors in Bohemia, but does not seem to know that 
Barrande too has described a distinct fauna in these lower beds, 
or their equivalent in age, and. places there very properly, as do 
all American geologists, the first degree or stage in the “ biologic 
development of our planet.” 
The author gives, among his characteristic fossils of the Tren- 
ton formation, Orthoceratites communis, of Wahlenberg, and re- 
fers the name to a figure of Cameroceras trentonense, evidently 
copied from Paleontology of New York, vol. i, pl. 56, fig. 4; 
fossil very unlike the O. communis in every respect. Still fur- 
ther, he cites it as common in New York, Pennsylvania, Canada, 
the Mingan Islands, on the coast of Labrador, and in Newfound- 
land, near the straits of Belle Isle. Now the form figured is a rare 
ossil, known only in a few specimens found in New York. 
The author cites Orthis testudinaria and Verneuili, Dalm., as 
equally in Europe and America.” If the author has been as 
careless of his localities as he has been in his citations of author- 
ities, we can judge very well of his accuracy in this case. e 
O.Verneuili is one of Eichwald’s species, and the fignre in Marcou’s 
book is copied directly, reduced in size, from Murchison and de 
Verneuil’s Russia and the Ural Mountains, vol. ii, pl. 12, fig. 1; 
and is there cited from two localities in Russia, viz., Reval and the 
sland of Dago. ‘This is the first intimation of its having been 
found in America; and as no locality is given, we may be per- 
mitted to discredit it altogether. Orthis testudinaria is an abund- 
ant species in Europe and America. : 
page 23, it is asserted that most of the blue limestone in 
the neighborhood of Cincinnati is of the Trenton formation. 
This was believed ten 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. ae 
Jn page 24, speaking of the Hudson river group and Utica 
slate, he says: “Fossils are rare in this division.” Perhaps no 
Portion of the palzeozoic rocks is more densely crowded with fos- 
Sils than this group when in an unaltered condition. In central 
and north New York, in “Upper Canada and Bay des Noquets,” 
the two latter localities cited by our author,—the fossils are ex- 
tremely abundant. While Mr. Marcou says the only fossils of 
Se rocks are Graptolites and fragments of Trilobites, it is 
shown in the Palezontology of New York that more than sixty 
Szais, Vol. XVII, No. 50.—March, 1854. 26 
