12 
ON THE FOSSIL FOOT-MARKS 
known that this formation encircles entirely in a peculiar manner, all the three anthracite 
coal basins of Pennsylvania, and Prof. Rogers so describes it, stating that “ it is enclosed 
between the ridges of Formation No. 9, on the one side, and on the other, those contain¬ 
ing Formation No. 12, composing the margin of the coal measures.” (2d Report, p. 66.) 
He describes “Formation No. 12,” as “conglomerates and sandstones immediately below 
the coal,” and states it to repose on the “Red Shale Formation,” (No. 11,) p. 67. 
A mass of coal plants exists immediately on the northern face of the heavy conglome¬ 
rate, here tilted ten degrees over the vertical, and forming the crest and “ back-bone ” of 
Sharp Mountain. This conglomerate mass is about one hundred and fifty feet thick at 
the western side of the road, below Pottsville. On the same road-side, about 1735 feet from 
these coal plants, is the face of the rock bearing these “ foot-prints,” tilted slightly over 
the vertical, and facing the north. It is proper to state, that the limestone of the Old 
Red Sandstone exists here about two feet thick, and underlies these “foot-prints” sixty- 
five feet. 
Sauropus primjEVus. PI. XXXI. 
Feet pacldydactylous. Anterior ones armed with five toes. Divarications of the first 
and second toes = 60°; of the second and the third, = 50°; of the third and the fourth, 
= 40°; of the fourth and the fifth, = 40°. Impression of the toes too much confused 
to measure correctly, varying from one and a half to two inches long. Length of the 
foot about three and a half inches. Breadth about three inches. Distance from the point 
of the first to the second toe, 1.9 inches; from the second to the third, 1.4 inches; from 
the third to the fourth, 1.2 inches; from the fourth to the fifth, 1 inch. Posterior feet 
armed with four toes. Divarications of the first and second, = 40; of the second and 
third, = 35°; of the third and fourth, = 50°. Length of the toes not ascertainable, owing 
to their obliteration by its impact with the impression of the anterior foot. Track of the 
posterior foot in a line and directly in advance of the anterior foot. The stride or step 
from toe to toe, 13 inches; from outside to outside, 8 inches. Length of the tail-marks, 
about 5 inches; breadth, three-quarters of an inch. 
Plate XXXII. 
This presents a reduced view of the slab, which is thirty-four by twenty-one inches, or 
rather less than one-fourth the natural size, and displays the regularity of the steps in a 
double row, as well as the librating tail-grooves, and the ripple-marks. 
Plate XXXIII. 
In my former communication to this society, I mentioned that there were other remains 
of organized matter in this rock. Obscure impressions of plants, small spots, with fila¬ 
mentous radiations and reed-like marks had been observed. In many places on the sur¬ 
face of the rocks, I observed rough nodules, concretionary masses, which I have since 
concluded may be fossil ova of batrachian reptiles. They are irregular ovoid bodies, and 
usually in pretty close approximation. In the specimen before me, the water in passing 
over these left lines indicating its direction. (Fig. 2.) Occasionally may be seen small 
