494 
PALEONTOLOGY OF ILLINOIS. 
I have said above that the relation of these fruits can not be traced to any 
other kind of vegetable remains, leaves, branches or trunks of the Coal Meas¬ 
ures, but there is, I think, a remarkable exception worth mentioning here. 
The shale overlying the coal of Cuyahoga Falls, Ohio, where Ptilocarpus sama- 
raiformis has been found with many others of the same genus, is, in some 
places, covered with a quantity of leaves of the peculiar Whittleseya elegans, 
Newb. These leaves, by their flabellate form, seem related to the genus Salis- 
buria, while the nervation resembles that of a Pterophyttum or Zamites. I con¬ 
sider it very probable that some of the above mentioned winged fruits are re¬ 
lated to these leaves, and that we have, therefore, two remarkable organs of 
species of the Conifer family. 
It appears, therefore, that if the Acrogenous plants did constitute the essen¬ 
tial part of the vegetation of the Carboniferous epoch, this vegetation had 
already representatives of the three essential classes of plants of our actual 
flora: the Phenogamous dicotyledonous, represented by Gymnosperms; the 
Phenogamous monocotyledonous, to which are referable species of Gordaites , 
Ncaggerathia and Trigonocarpum , and the Cryptogamous, represented by the 
three families of Equisetacem , Filices and Lycopodiacem. And from all appear¬ 
ances, we have to admit the similarity of characters and uniformity of the 
entire flora of the Carboniferous period. For it does not appear that any of 
the species known from our Coal 31easures have been transported from a dis¬ 
tance, either by water or by the winds, and casually deposited in sands or clays 
of the coal swamps. The leaves and fruits are generally found in groups, a 
number of their remains being together, and covering a limited area, as if 
originating from trees or plants grown at the place around which these remains 
are spread, and, as it has been remarked above, all the species of fossil trees 
as yet examined from the sandstone, are referable to genera known from shale 
overlying the coal strata. 
In pursuing the same mode of investigation, I have still to make some re¬ 
marks on the affinity of our new species and genera of fossil plants from Illi¬ 
nois, in addition to what has already been said in the detailed description of 
each. As our table shows, by far the greatest number of our new species have 
been found in the concretions of Mazon creek, from which it is reasonable to 
infer that the preservation of many of these species is due to their mode of fos- 
silization, and that the same kind of plants may have been constituents of the 
vegetation of the coal in other countries, though their remains have not as yet 
been found elsewhere. Of species of Neuropteris , for example, described and 
figured in the second volume of this Report: Neuropteris Evenii , N. pachyderma 
and N. verbenmfolia , all from Mazon creek, have been omitted by Schimper in 
his enumeration; and yet, though the two first have not been elsewhere discov¬ 
ered, their preservation is so remarkable, and their distinctive characters so 
