370 L. Lesquereux on the Coal Formations of N. America. 
Cordaites borassifolia Ung., Knorria imbricata Sternb., and some 
undeterminable stems. From these plants, six have been found 
also above the conglomerate series, ascending to coal No. 1B, or 
even higher. They are Stigmaria anabathra, var. undulata Gopp., 
and var. minor Gépp., Lepidodendron Worthianum Lsqx., 
imbricala Sternb., Calamites, Suckowii Brgt. and Cordattes borassi- 
folia Ung. These two last species are present in the whole thick- 
“ness of the coal measures, as high at least as the 12th coal. 
AsI have said before, no coal has been seen as yet formed be- 
low the 3d Archimedes limestone. But just overlying it, a bed 
of coal is generally present over the whole extent of the Western 
coal-fields. In Arkansas, this is the only workable bed of coal, its 
thickness varying from 18 inches to 43 feet. In the western 
part of the Eastern coal-basin of Kentucky, and also in Virginia, 
two, even three beds of good coal have been formed below the 
millstone grit. All the species of fossil plants of the shales of 
these coal strata have been found also in Arkansas. At Potts- 
ville and Mauch Chunk, near the eastern margins of the coal- 
fields, the coal is formed between strata of conglomerate, and 
even at the base of this formation. : 
The shales of the subeonglomerate coal contain not only re- 
mains of trees of large size, like the subcarboniferous sandstone, 
but thus early and simultaneously many of the species of ferns 
hich become more and-more abundant above the conglome- 
glomerate. It is therefore evident that a separation of the sub- 
conglomerate coal, as a peculiar formation and under a peculiar 
name, is contrary to paleontological evidence. Like every other 
eculiar to it. 
Two species of Lepidodendron, two of. Sigillaria, one of Sphe- 
nophyllum, two species of Trigonocarpum, one very 
carpum, one Stigmaria, one Alethopteris, and three or four Sphe- 
nopleridee.* In theshales of this lowest bed of coal, near Frog 
g to the State 
* All th i i , 
e new species of this coal, or at least most of them in the second 
, belon 
Geological survey of Arkansas, and are reserved for publication 
volume of that Report. 
