OF NORTH AMERICA. 
89 
ment. We may briefly run over a few of the earlier pages, and take a cursory glance at the map, for 
the benefit of the science, mentioning some of the errors, omissions, or objectionable points that have 
struck us. 
In his introduction, after mentioning Maclure, Mr. Marcou speaks of Conrad and Lea, (p. 14) cele- 
brated conchologists of Philadelphia, and leaves out Morton altogether. He then observes that Jackson 
and Alger published in 1828 a geological description of Nova Scotia, etc., and adds «Such nearly was 
the condition of geology in America when Murchison published his celebrated book entiled the Silurian 
System,# -leaving it to bo inferred that from 1828 to 1839, when Murchison’s work appeared, nothing 
had been done by geologists in America: -notwithstanding the publication in this period of the Final Re- 
port on the geology of New Jersey , the first Final Report on Massachusetts , the Annual Reports of 
Pennsylvania, Now York, Ohio, Michigan, Tennessee, 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 author says, « Troost, Vanuxem and Eaton wore 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.)) Sow 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 important results , nothing is more entirely un- 
founded than the above quoted assertion ; what they did could not by any possibility have served as a 
foundation for maps and memoirs subsequently 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 be- 
ginning a clearer idea of the age of our geological formations, as compared with Europe, than any 
other geologist. 
The map of Hyrem Lawrence, which is next mentioned, in terms of high praise, is essentially co- 
pied from a map made by Dr. D. D. Owen, and published in the Transactions of the Geological Society 
of London. 
We proceed to the body of the work. 
The Lingula antiqua, our author says, «is found in Now York, Michigan and Wisconsin.# We do 
not know of it in Michigan ; — perhaps in the same locality with Lingula prima (Foster 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. The last sentence in the same paragraph roads thus : « Its thickness varies 
with the different localities in which it is found, and depends on the more or less horizontal position 
of the bed ; nevertheless it may be said to vary from 500 to 2000 feet. » Prof. Rogers estimates this 
rock in Pennsylvania with doubt at 1000 feet, and in many parts of the United States it varies from 
150 to 300 feet. Dr. Owen estimates the thickness on the Mississippi at much loss than 1000 feet, and 
wo do not know any authority for believing it greater than this. Why the thickness should depend on 
the more or less horizontal position of the bod , is what we do not comprehend. 
Under the Trenton Limestone, page 22, wo find, «lt is in this division that for the first time is pre- 
sented a complete fauna, representing the first degree of the biologic development of our planet. The 
first division of the Lower Silurian (i. e. Potsdam) offers only a few species of animals, rarely to bo 
found, and mostly in a bad state of preservation.# 
The writer appears to be ignorant of what Dr. Owen has discovered in those strata on the upper 
Mississippi, viz.: Trilobites, Corals, Crinoids, Orthis, Lingula, etc. The Lingula are in a most perfect state 
of preservation; and in numbers of individuals unsurpassed in any formation of any period. The author 
speaks of Rarrande’s labors in Rohemia, but does not seem to know that Barrando 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 Trenton formation, Orthoceratites communis, 
12 
