Marcou’s Geological Map. 205 
We will say nothing of our author’s attempts to systematize our 
mountain chains; if we needed a parody on Elie de Beaumont 
and his systems of mountains, we have it here. j 
Mr. Marcou lameuts the want of accurate topographical maps, 
map any mountain chains, but has “ written ear the places oc- 
cupied by the different chains of mountains, the names of those 
chains.” For the same reason we suppose, or some other equally 
cogent, he has given no lines of States, but has written the 
names of the various states somewhere near the places occupied ’ 
by them respectively. This allows the limits of the various ge- 
ological formations to be laid down any where near the places 
they occupy, without giving the pupil or the critic the means o 
determining their accuracy within many miles, a device perhaps 
convenient for the author, but not so for the student. 
e map in its geology is little more than a reproduction of 
that published by Lyell in 1845, and in many respects it is infe- 
rior to that. As we have remarked respecting the text, the sand- 
stone of Lake Superior is represented as the New Red, or of the 
age of that of the Connecticut, New Jersey, &c. -But besides 
this, he continues a belt of the same formation across from the 
head of Lake Superior, by the sources of Red river to the head 
of the Coteau des Prairies. In that direction he again takes up 
the same formation in the Wind River chain of mountains. In 
both these instances, there is vot the slightest authority for sup- 
posing such belts of sandstone formation, and particularly any of 
the age of the New Red. 
Without the slightest reason or authority, and in the face of 
facts, he runs a belt of lower carboniferous from the coal field of 
Michigan to the northeastern part of the Illinois coal field, aud 
another from the eastern side of the Lilinois coal field to the 
northwestern side of the Alleghany coal field. The latter is a ~ 
Worse error than the former, for he positively traces it across a 
broad belt of Silurian rocks which are a prolongation of those to 
the north of Cincinnati, and which are clearly followed north- 
eastward to the lake shore and the islands west of Sandusky. 
n like manner he traces another similar belt of carbouiferous 
tocks to the southward of the Cincinnati axis, connecting the 
east and west coa! field. The idea many years since promulga- 
ted that the Waverly sandstone of Ohio did pass around to the 
South side of this elevation, was long since proved otherwise ; 
and no geologist for the past seven years would have ventured to 
republish an exploded error. 
The union of the coal field of Missouri and Iowa with that of 
Arkansas is without authority ; and so also the exteusion of 
lower carboniferous over so great a breadth of territory to the 
