360 Geological Survey of the State of Ohio. 
at random over the bottom of the lake, estuary or sea; so that a 
jaw would be found in one place, a rib in another, a humerus in 
a third—all included, perhaps in a matrix of fine materials, where 
there may be evidence of very slight transporting power in the 
—— or even of none, but simply of some chemical precip- 
itate. 
wee these remarks we take leave of the report of Mr. Briggs; 
we haver d it with pleasure and profit. 
We have described the different groups embraced in the report 
of Mr. Briggs. We now proceed to describe those above. 
VI. Buhr.—This rock forms the dividing line between the up- 
per and lower coal series. In our remarks upon Dr. Hildreth’s 
report, we gave the principal characteristics of this rock. 
VII. Upper coal series.—These, like the lower coal series, are 
composed of sandstones, shales, coal, iron ores, and limestones. 
The coal is the most valuable mincral in this group. There are 
at least, four distinct beds, capable of being wrought, and of a 
good quality. In this group, is included the cannel coal of Cam- 
bridge, described in a former number of this Journal. The lime- 
stones in this series, are more abundant than in the lower, and ex- 
ert a beneficial influence on the soil. The Belmont Hills are noted 
for their productiveness. The iron ores included in this group, are 
not as abundant as in the lower series—nor are they wrought for 
manufacturing purposes. The organic remains of the two groups, 
do not differ essentially. In the limestones, we meet with the 
Encrinite, Delphinula, Spirifer, Productus, Terebratula, &c. We 
have detected no terrestrial plants. 'The sandstones often contain 
the stems of coal plants. The most common are Stigmaria ficoi- 
des, Lepidodendron Sternbergi? and several varieties of Sigil- 
aria. From the shales, beautiful impressions are obtained. The 
principal are Hquiseta, Calamites, several species of Filices, and 
Lycopodiacee, and perhaps, one or two species of Palne. Two 
or three species of Astorophyllites have been found. Fucoides are 
not uncommon. 
VIL. Tertiary deposits.—Under this head, we place the pral- 
ries or barrens, in the western portions of the State, the pebble 
beds and boulders of primitive rocks, so abundant in some parts 
of the Scioto valley, as well as those deposits, in which the 
* 3. Lyell, Lond. Ed. 232. 
