178 GEOLOGY OF OHIO. 
terts obliqua, Bunb.; Annularia calamitoides, Sch.; A. sphenophylloides var. 
brevifolia, Brong.; Neuropteris flecuosa, Brong.; N. Cistit, Brong.; N. Granger, 
Brong.; Alethopteris nervosa, Brong.; A. aquilina, Brong.; A. Serliz, Brong. ; 
Sph. Schlotheimi, Brong., with many others not found, so far as my observa- 
tions have extended, in the lower coal. Most of the species here enu- 
merated run up through the series, and no subdivision of the flora seems 
to me possible above the line of Coal No.4. For example, the roof shales 
of Coal No. 8 at Pomeroy are filled with the same species of plants found 
over Coal No. 4 in the valley of Yellow Creek, viz., Newropteris flexuosa, 
N. cordata, Cordaites borassifolia, Annularia calamitoides, Cyclopteris fimbri- 
ata, Pecopteris arborescens, etc. 
The upper flora of the Coal Measures is characterized by poverty in 
Sigillaria and Lepidodendron—genera which form the most striking fea- 
tures in the lower flora—and by the presence of Psaronius, which occurs 
locally in great abundance over Coal No. 8, but is unknown in the Lower 
Coal Measures. 
The grouping of the coal plants at different horizons is generally a 
better guide than the presence or absence of individual species. This, 
however, could only be shown by long lists of names, and most of these 
would be repeated again and again. Even when, with considerable 
trouble, the coz! plants of northern or southern Ohio had been stratified, it 
would be found that the grouping made would hold good for only that one 
locality. This will appear plainly from a comparison of the vertical dis- 
tribution of the coal plants of Pennsylvania reported by Mr. Lesquereux 
with that which I have described as prevailing in Ohio. Many of the 
species which he finds there characteristic of the lowest workable coal, I 
find here, only at a higher level, and vice versa. By reference to the Hh- 
nois geological reports—which are enriched by copious descriptions and 
notes on the coal flora by Mr. Lesquereux—the same discrepancies will 
be observed; and we must, therefore, conclude that the flora of the Coal 
Measures, like the fauna, is distributed through the strata in such a way 
that no well-defined horizons are discernible in it. 
The animal remains of the Coal Measure epoch consist for the most 
part of mollusks, for the reason that they inhabited the water, usually 
in large numbers, and their structures were mainly hard and imperish- 
able; and thus generation after generation has been buried and preserved 
in the sedimentary deposits. The molluscous fauna of the Coal Measures 
has been carefully studied in several of our Western States, and though 
the collections made in Ohio are large, and they have been passed in re- 
view by one of the most learned and accurate of living paleontologists, 
comparatively little has been found that was new or of special interest. 
