found in Sandstone in Dumfriesshire. 201 



taken, when they are compared with those which are more dis- 

 tinct. I have unfortunately taken no accurate measurement of 

 this track ; but from an imperfect specimen now transmitted *, 

 it appears that the distance from the hind to the fore foot, when 

 most nearly in contact, was about 1 foot 9 inches, while the 

 breadth across from the line of the right foot track to that of 

 the left, was somewhat more than 7 inches ; and if I might be 

 allowed to speak from recollection, I should say that what I 

 have loosely called the animal's step, for want of a better word, 

 that is, the distance between the fore and hind feet, supposing 

 them to be at their stretch, could not be less than five feet. The 

 layer on which the impressions are made, happens to be only a 

 little more than half an inch thick, and it has naturally no ad- 

 hesion to the under stratum. In attempting, however, to raise 

 a specimen from its bed, I found that the two strata were so in- 

 timately united wherever the prints of the feet occurred, that it 

 was impossible to separate them without breaking. It seemed 

 as if the weight of the animal, or its efforts in ascending, had 

 occasioned the thrusting of its feet entirely through the upper 

 into the under layer ; and on forcing the strata asunder, this 

 supposition was confirmed by the curious fact, that the matter 

 of the under layer, displaced doubtless by the sinking of the feet, 

 was discovered to be heaped up in a ridge-like form round the 

 insertion of the animal's heel, having made way for itself, when 

 forced back, by causing a corresponding concave impression on 

 the under face of the upper stratum. 



With regard to the species of animals whose tracks have 

 been so wonderfully preserved, I do not think myself competent 

 to offer any conjectures of my own ; but having been in corre- 

 spondence with one of the first geologists of the age (to whom I 



* Specimen marked B, on which there is also the track of a small animal ascend- 

 ing. 



VOL. XI. PART I. C C 



