310 FOSSIL FOOT-PRINTS [CHAP. XXXVII. 



successive foot-steps of the same animal. Everywhere 

 there was seen a double row of tracks, occurring in 

 pairs, each pair consisting of a hind and 

 fore foot, and each being at nearly equal 

 distances from the next pair. The toes in 

 each of these parallel rows turn the one 

 set to the right, the other to the left. It 

 is instructive to compare these impressions 

 with those which had previously been met 

 with in an ancient European rock (although 

 one of less antiquity than the coal-form 

 ation), namely, the new red sandstone or 

 Trias of Saxony and Cheshire. The ac 

 companying figure (fig. 14.) represents the 

 Saxon Cheirotherium, so called by Professor 

 Kaup, because the marks both of the fore 

 and hind feet resemble the shape of a 

 human hand. Now in these European 

 hand-shaped foot-marks, both the hind 

 and fore feet have each five toes, and 

 the size of the hind foot is about five 

 times as large as the fore foot ; but in 

 the American fossil (fig. 13.), the posterior 

 foot-print is not nearly twice as large as the an 

 terior, and the number of toes is unequal, being 

 five in the hinder and four in the anterior foot. 

 In the Greensburg animal, as in the European 

 Cheirotherium, the fifth toe stands out nearly at a 

 rio-lit ano-le with the foot, and somewhat resembles 



O & 



the human thumb. On the external side of all the 

 Pennsylvania!! tracks, both the larger and smaller, 

 there is a protuberance like the rudiment of another 



