On the Foot-marks of Animaih in Rocks. 183 



in great abundance. On causing two portions of the stone to 

 be removed at hazard, we found very distinct marks on the 

 under side of both. They are not impressed, but rather form 

 knobs or nuclei, for they project from the surface in proportions 

 varying from half an inch to three inches. 



It is sometimes necessary to free the stone from the soft ad- 

 hering clay, before a distinct view of the marks can be obtained. 

 It is always the under side of the foot that is seen. The animal 

 must therefore have made the impression in the clay, (probably 

 when the surface was a marsh) ; a torrent of sand, suspended in 

 water, had then run over it, and covering all the country, in- 

 sinuated itself into the impressions. In this way, when the sand 

 became indurated, the sandstone formed in the impressions must 

 needs have adhered to the upper bed, and produced upon it 

 these projecting marks. It is on this bed alone that these marks 

 are found ; they have never been observed either in the super- 

 incumbent sandstone, nor in any of the inferior beds of sand- 

 stone which have been quarried. 



It is easy to distinguish the feet of four different species of 

 animals, but I shall only speak of the most common kind, of 

 which I have seen nearly a hundred. 



Two feet are always found alike ; a larger hinder one about 

 six inches in length, and a fore one about one-half that size. 

 They have five toes. The thumb is remote from the others, 

 and forms nearly a right angle with them. The two thumbs of 

 one pair of feet are always directed to the same side, but the 

 thumbs of the following pair are directed to the opposite side ; 

 the animal must therefore have walked with an ambling gait. 

 An extraordinary fact is, that the pairs of feet follow each other 

 in a straight line, so that these creatures may be said to have 

 walked enjhuchant. 



M. Weigmann, who has examined the stone bearing these 

 marks, brought to Berlin by M. Weiss in the month of May, 

 and who has given a notice of them in his Journal of Natural 

 History, refers the animals which produced them to the class of 

 Mammiferae ; but M. le Compte de Munster places them in the 

 class Amphibia. The latter opinion appears to me to be pre- 

 ferable to the other. All the mammiferae with a thumb remote 



