on Footsteps of the Chirotherium. 149 



port are of opinion, that each of the thin seams of clay in which the 

 sandstone casts were moulded, formed successively a dry surface, 

 over which the Chirotherium and other animals walked, leaving im- 

 pressions of their footsteps ; and that each layer was submerged by 

 a depression of the surface. The loAvest seam of clay was so thin, 

 that the marks penetrated into the subjacent sandstone. The fol- 

 lowing account is then given of a hind foot and a fore foot, selected 

 from slabs in the Museum of the Royal Institution, Liverpool. 



Hind Foot, consisting of five digits ; one of which, from its resem- 

 blance to a human thumb, has been generally distinguished by that 

 designation. 



Inches. 



Total length from the root of the thumb to the point of the se- 

 cond toe 9 



Extreme breadth from the point of the thumb to the point of 



the fourth toe 6 ' 



Breadth across the toes 5 



Breadth across the palm 3 



Length of the curved line extending from the root of the thumb 



to its point 6^ 



Breadth of the ball of the thumb 1^ 



Relief of the ball of the thumb from the surface of the slab. . . -i- 



Length of the first toe from the root to the point b^ 



Length of the second ditto 5^ 



Length of the third ditto 4 



Length of the fourth ditto 2^ 



Average breadth of the first three toes 1 



Average breadth of the fourth toe rather less than 1 



Relief of the second toe, which presents the greatest promi- 

 nence Yn 



One hind foot has been observed which measured 12 inches in its 

 greatest length. 



Judging from the appearance of the casts, the sole of the foot 

 must have been amply supplied with muscles, the casts of the ball 

 of the thumb and the phalanges of the fingers being prominent. 

 The digit, which has been called a thumb, is of a tapering shape, 

 and is bent backwards near the extremity, where it ends in a point. 

 It is extremely smooth, and there is no satisfactory evidence of either 

 a nail or a claw. The toes are thick and strong, and had probably 

 three phalanges each, and at the terminations are traces of stout, 

 conical nails or claws. The sole of the foot is supposed to have 

 been covered by a slightly rugose skin, the folds of which are stated 

 to be distinctly visible in the casts of the toes. 



Fore Foot. Perfect impressions of the fore feet are extremely 

 rare, owing either to the animal having used those feet lightly, or 

 to the imjjressions having been obliterated by the tread of the hind 

 feet. The best preserved cast exhibits a thumb and tliree toes, 

 being deficient of the fourth. The dimensions, which are generally 

 half those of the hind foot, are as follows : 



