182 Parallelism of the Paleozoic Deposits 
caped the American geologists, and that which still farther con- 
firms it, is the occurrence of the fucoids and ripple marks, with 
which the surface of the beds is often covered; unquestionable 
evidence of the vicinity of shallow waters (bas-fonds, low bot- 
toms) and of shores. An important circumstance is that these 
fucoids and ripple marks are observed at all stages, from the Pots- 
dam sandstone to the Portage group; so that it becomes incon- 
testible that the whole mass of the Paleozoic formation, however 
who attribute to this circumstance, rather than to the action of 
time, the differences which distinguish the Silurian fauna from 
those which have followed ?” 
“ Composition of the Paleozoic formation in the states of Ohio, 
Kentucky, and Indiana.—Between the great coal basin which 
occupies a part of Pennsylvania and of Ohio, and that of Illinois, 
rises an anticlinal axis which separates them, and which elevates 
all the more ancient beds even to the lower stage of the Silurian 
system. It is not an axis of entire dislocation; the beds continue 
to remain apparently horizontal, their dip being only fifteen or 
sixteen feet in the kilometer, but this dip being in opposite di- 
rections on the two sides of a line nearly north and south, which 
by Cincinnati, is sufficient to bring to light throughout a 
great extent, in wide bands, the inferior parts of the Paleozoic 
strata. Nothing is more interesting, when once familiar with the 
rocks and the fossils in the state of New York, than to trans- 
port one’s self one hundred and fifty, or two hundred leagues to 
the west to observe the changes which this series presents, and to 
seek for the cause which we will do in the briefest manner.”* 
of the carboniferous period, appear only in the Chemung group, and these are ve- 
ay 
mo We recommend persons who desire more details on this subject, to read the 
two very interesting memoirs of Mr. J. Hall, one upon the identity of the forma- 
tions of the west in the United States, with those of the state of New York, 
printed in the 'l'ransactions of the American Associ logists, &e.; tl 
other upon the nature of the strata and the distribution of fossils in the ancient 
formations of the United States, inserted in the rnal of the Boston Societ 
Nat. Hi ve had occasion to recognize the exactness of the ob- 
servations of this able geologist, and we only differ from him in opinion upon 
e true equivalents of the black bituminous shales, and of the prey 
mass of the micaceous sandstones which overlie them in the states of Ohio, in- 
diana and Kentucky.’ 
hl a 
. nak ut be- 
tween this rock and the knobs near New Albany, there is a thickness of four or five 
hundred feet, the lower part of which is shaly, of a greenish color, and any 
