Tracks of Animals in the Forest Marble. 545 



escaped obliteration. I throw out, merely as a hint, the idea 

 that the rippled surfaces were left dry and became partially 

 consolidated under the influence of the air and sun, and that 

 the seams of clay which cover them were the first deposit of 

 the rising tide, bearing before it the mud washed into the sea 

 at low tide from the mouth of some neighbouring river. The 

 alternate laminae of limestone will, in this case, have been de- 

 posited during the temporary stillness of the water at high tide. 



I shall not make an attempt at determining to what yenus or 

 even class of animals these tracks are to be referred ; whether 

 marine, terrestrial) or amphibious. It will be observed, that the 

 foot-marks vary considerably in size, but are uniformly found 

 in double lines, parallel to each other, and each shewing two 

 indentations, as if formed by sharp claws, with occasional traces 

 of a third claw. In the most perfect specimens (fig. 2, pi. 5) 

 there is also a third line of tracks, midway between the other 

 two, as if produced by the tail or the stomach of the animal 

 touching the ground at each bound ; and where the animal 

 passed over the sharp ridges of the wrinkles, they are flattened 

 and brushed down, as if by a moving power of a considerable 

 force. Thus a ridge between b and d (fig. 2, pi. 5) has been 

 flattened, and there is a hollow at c, on the steep side of the 

 ridge, which may have been produced by the animal slipping 

 down, or climbing up the acclivity. 



I leave it entirely to more experienced zoologists than myself 

 to determine, or even to guess at the animal to which we must 

 refer these remarkable tracks. 



The long and sinuous traces to which I previously referred 

 (fig. 1, pi. 5) are to me of equally doubtful origin. I should be 

 inclined to suppose them the produce of some annulose or mol- 

 luscous animals burrowing in the sand, were it not for their great 

 analogy to some very slightly different marks in the same beds, 

 which, from their feathery appendages, seem to be broken por- 

 tions of the long tentacula of some species of encrinite. 



The further examination and comparison of specimens will 

 probably enable us to clear up these doubtful points. 



I shall content myself with remarking on the number of in- 

 teresting memoranda here brought together, often within the 

 compass of a single slab, of the remote time when the waves of 



