192 PALEONTOLOGY. 



same animal, were observed in the same quarry. Everywhere 

 there was a double row of tracks, and in each row they occur 

 in pairs, each pair consisting of a hind and fore foot, and each 

 being at nearly equal distances from the next pair. The hind 

 foot-print is about one-third larger than the fore foot-print : 

 it has five toes, but the front one only four ; some of them 

 exhibit a stunted rudiment of the innermost toe or " pollex," 

 which is the undeveloped one. The outermost toe in the 

 hind foot-print is shorter and rather thicker than the rest, and 

 stands out, as it does in fig. 83, like a thumb on the wrong 

 side of the hand. 



With this general resemblance to the footprints of Laby- 

 rinfhodon, from the new red sandstones of Europe, there are 

 well-marked distinctions. In the first place, the right and left 

 series of impressions are wider apart, indicative of a broader- 

 bodied animal. The front print in Batrachopus has only four 

 well-developed toes instead of five, as in Lalyrinthodon ; it 

 is also proportionably larger, — the fore foot in Ldbyrinthoclon 

 being less than half the size of the hind foot. The distance 

 between the fore and hind print of each pair, and of one such 

 pair from the next on the same side, is nearly the same in 

 Batraclwipiis and Labyrintlwdon. 



Genus Saukopus, Eogers. — Very similar foot-prints were 

 discovered and described by Mr. Isaac Lea in a formation of 

 red shales, at the base of the coal measures at Pottsville, 78 

 miles N.E. of Philadelphia, These are of older date than the 

 preceding, inasmuch as a thickness of 1700 feet of strata 

 intervenes between the foot-prints at Greensfield and the 

 Pottsville impressions. 



Professor H. D. Eogers, in 1851, announced his discovery 

 in the same red shales, between the Devonian and Carboni- 

 ferous series, of three species of four-footed animals, which he 

 deems to have been rather saurian than batrachian, seeing 

 that each foot was five-toed ; one species, the largest of the 



