found in CorncocMe Muir^ Dumfries-shire. 87 



of their origin, his tortoises, in going down a declivity ove? 

 wet sand, having made " almost exactly the same impres- 

 sions." 



There are some curious facts connected with this phenom- 

 enon which have not yet been mentioned, and which the lim- 

 its I must prescribe to myself will not allow me to do more 

 than enumerate: — 



1st, In most instances the counter impressions are distinct- 

 ly marked in relief on the under surface of the layer cover- 

 ing the foot prints, these projections corresponding to the 

 cavities below as exactly as a cast to its mould. 



2i?, The impressions never occur but on what the workmen 

 call a clay face, by which is meant a stratum, the outer coat 

 of which has a slight admixture of clay, rendering it harder 

 than the rest of the rock, accompanied sometimes wilh a this 

 layer of soft clay in the seam between the under and up- 

 per stratum. 



3d, All the tracks are constantly in a direction either up or 

 down, sometimes inclining a very little either to the right 

 or left, but never running across the slope in any gi-eat de- 

 gree. 



4th, In most of the impressions there are marks of the 

 matter being displaced by the foot-marks, and wherever 

 such an appearance occurs, the matter is found to have been 

 carried directly downwards, with reference to the present 

 inclination of the quarry. 



These two last circumstances, as well as that of the sli^ 

 ding tracks, prove that the strata must have been rery much 

 inclined, while in a soft state, and while in the act of form- 

 ing though this is contrary to the received opinion as to the 

 formation of sandstone. 



5th, The sand must have possessed very considerable tena- 

 city, and have even been sometimes skinned over with a stiff 

 coat, for in one of the specimens preserved at Ruthwell, the 

 claws of the animal had evidently broken througli the outer 

 coat at every step, and in two others, where the hind paws 

 have rested on the matter just displaced by the fore paws, 

 their pressure, instead of obliterating the appearance of su- 

 peradded matter, has merely caused an indentation of the 

 part rested on. 



6th, There are continuous strata of sandstone resting on 

 those in which the impressions are found, for the distance of 

 not less than a quarter of a mile, all of which must have beea 



