26 C. Lyell on Footprints in the 
overlying useless shale. Between the slabs of stone, which are a 
few inches thick, are thin parting layers of a fine unctuous clay 
well fitted to receive and retain faithful impressions of the feet of 
animals. About twenty three footsteps have been observed, some 
more and others less distinct. One of these was seen by Dr. 
King, to be impressed on the upper surface of a layer of clay, but 
the specimen was unfortunately left exposed to the weather and 
destroyed. The other Cheirotherium footsteps stand out in re- 
lief from the under surface of a bed of sandstone, and are ac- 
companied by small mud-veins which have been described: as 
fucoids for which they were mistaken. They are in fact casts of 
those cracks of various sizes which are produced by the drying 
and ‘shrinking of mud. As the footprints are traversed and oc- 
casionally distorted by these veins, it is evident that the shrink- 
age took place after the animal had walked over the mud. There 
is every where seen a double row of tracks, which occur in pairs, 
each pair consisting of a hind and fore foot, and each being at 
nearly equal distances from the next pair. The toes, on each of 
these parallel rows, tor; the one set to the — the other to the 
left. 
The geological position of this thats is sertbeiny clear. It 
is situated in the midst of the Apalachian coal field, and there is 
no formation to be seen, except the carboniferous, for a consid- 
erable distance in any directions The beds are gently inclined 
to the 8. E., and occur on the side of one of those troughs which 
intervene het weeil two anticlinal folds or ridges which are not 
only found in the principal chain of the Alleghany mountains, but 
also, as in this instance, in the lower and less hilly country im- 
mediately west of the mountains. The sandstone and shale con- 
taining the footsteps, crop out from beneath the main or Pittsburg 
seam of coal, which is about nine feet thick, and has been worked 
at its outcrop in the immediate neighborhood. This coal is less © 
than a hundred feet above the sandstone, and there are several 
other seams of workable coal which lie at lower levels; and im- 
pressions of Lepidodendron, Sigillaria, Stigmaria, Cailamnites; ferns, 
and other carboniferous plants, have been found both above and 
rested the level of these reptilian footsteps. 
_ The second locality which I visited, where the supposed fossil 
otprints of birds and of quadrupeds resembling dogs, were ob- 
‘fo 
served by Dr. King, is armen reuse a mile- ms noe town of 
