200 Marcow’s Geological Map. 
nual Reports of Pennsylvania, New York, Ohio, Michigan, 'Ten- 
nessee, and Maine, which gave altogether a very good general 
view of the Geology of a great part of the United States. 
On page 15, the adthor says, “Troost, Vanuxem and Eaton 
were also among the first to compare the American formations 
with those of Europe, and laid the true foundations on which all 
the geological maps and memoirs published on this side of the 
Atlantic for sixteen years, have been constructed.” Now as one 
example in point, Troost identified the Silurian of Tennessee 
with the carboniferous of Europe, and Eaton the Silurian of New 
York with the New Red Sandstone. Giving every due credit to 
these named geologists for their labors, which in many respects 
had insportant results, nothing is more entirely unfounded than 
the above quoted assertion ; what they did could not by any pos 
sibility have served as a foundation for maps and memoirs subse- 
queutly published. Mr. Vanuxem did indeed, in the division of 
the Cretaceous, identify that formation of New Jersey with the 
same in Europe; and had from the beginning a clearer idea of 
the age of our geological formations, as compared with Europe, 
than avy other geologist. — 
The map of Byrem Lawrence, which is next mentioned, in 
terms of high praise, is essentially copied from a map made 
Dr. D. D. Owen, and published in the Transactions of the Geo 
logical Society of London. 
e proceed to the body of ‘the work. 
The Lingula antiqua, our author says, “is found in New 
York, Michigan and Wisconsin.” We do not-know of it in Miehi- 
gan ;—perhaps in thesame locality with Lingula prima (Fostet 
and Whitney’s Report) in the Lake Superior region, where it 
occurs in a sandstone which Mr. Marcou further on calls the New 
Red Sandstone. ‘lhe last sentence in the same paragraph re 
on the Mississippi at much less than 1000 feet, and we do 0 
know any authority for believing it greater than this. Why the 
thickness should depend on the more or less horizontal positio2 
of the bed, is what we do not comprehend. . ae 
Under the Trenton Limestone, page 22, we find, “It is in this 
fi 
planet. The first division of the Lower Silurian ie Potsdam 
offers only a few species of animals, rarely to be found, and mostly 
ation.” i 
in a bad state of preserv 
