510 AIR-BREATHERS IN THE COAL. [Ch. XXV. 



1851 that he had discovered other footprints, referred by him to three 

 species of quadrupeds, all of them five-toed and in double rows, with 

 an opposite symmetry, as if made by right and left feet, while they 

 likewise display the alternation of fore foot and hind foot. One spe- 

 cies, the largest of the three, presents a diameter for each footprint 

 of about two inches, and shows the fore and hind feet to be nearly 

 equal in dimensions. It exhibits a length of stride of about nine 

 inches, and a breadth between the right and left footsteps of nearly 

 four inches. The impressions of the hind feet are but little in the 

 rear of the fore feet; The animal which made them is supposed to 

 have been allied to a Saurian, rather than to a Batrachian or Chelo- 

 nian. With these footmarks were seen shrinkage cracks, such as are 

 caused by the sun's heat in mud, and rain-spots, with the signs of the 

 trickling of water on a wet, sandy beach ; all confirming the conclu- 

 sion derived from the footprints, that the quadrupeds belonged to air- 

 breathers, and not to aquatic races. 



In 1852 the first osseous remains of a reptile were obtained from 

 the coal-measures of America by Dr. Dawson and myself. We de- 

 tected them in the interior of one of the erect Sigillarige before alluded 

 to as of such frequent occurrence in Nova Scotia. The tree was about 

 2 feet in diameter, and consisted, as usual, of an external cylinder of 

 bark, converted into coal, and an internal stony axis of black sand- 

 stone, or rather mud and sand stained black by carbonaceous matter, 

 and cemented together with fragments of wood into a rock. These 

 fragments were in the state of charcoal, and seem to have fallen to the 

 bottom of the hollow tree while it was rotting away. The skull, jaws, 

 and vertebrae of a reptile, probably about 2-j- feet in length (Dendrer- 

 peton Acadianum, Owen), were scattered through this stony matrix. 

 The shell, also, of a Pupa (see fig. 561, p. 512), the first land-shell ever 

 met with in the coal or in beds older than the tertiary, was observed 

 in the same stony mass. Dr. Wyman of Boston pronounced the rep- 

 tile to be allied in structure to Menobranchus and Menopoma, species 

 of batrachians, now inhabiting the North American rivers. The same 

 view was afterwards confirmed by professor Owen, who also pointed 

 out the resemblance of the cranial plants to those seen in the skull of 

 Archegosaurus and Labyrinthodon* Whether the creature had crept 

 into the hollow tree while its top was still open to the air, or whether 

 it was washed in with mud during a flood, or in whatever other man- 

 ner it entered, must be matter of conjecture. 



Footprints of two reptiles of different sizes had previously been ob- 

 served by Dr. Harding and Dr. Gesner on ripple-marked flags of the 

 lower coal-measures in Nova Scotia, evidently made by quadrupeds 

 walking on the ancient beach, or out of the water, just as the recent 

 Menopoma is sometimes observed to do. 



The remains of a second and smaller species of Dendrerpetoit, D, 



* Geol. Quart. Journ., vol. ix. p. 58. 



