456 PROCEEDINGS OF THE aEOLOGICAL SOCIETY. [DeC. 15 



I am at a loss to find an exact parallel for this peculiar combina- 

 tion of characters in any group of recent or fossil Beptilia. Among 

 the tertiary and recent reptiles I know of nothing at aU like it ; and 

 all the mesozoic Crocodilia with whose dermal armour that of Sta- 

 gonolepis exhibits such a close resemblance, present no important 

 divergence from the typical crocodilian structure of the coracoid, 

 while their slender feet have undergone the opposite modification to 

 that which appears to have taken place in Stagonolepis. The Ena- 

 liosauria and Pterodactylia afibrd us no terms of comparison ; and 

 from the Dinosauria, with which Stagonolejpis presents one or two 

 similarities, it is broadly separated by the especially crocodilian cha- 

 racters of its scutes and sacrum. These characters equally separate 

 it from all the Triassic and Permian Beptilia which have hitherto 

 been described. What little we know, at present, of the laws by 

 which the distribution of life in past time was governed, does not 

 seem to me to enable us to deduce from the existing data any con- 

 clusion as to the precise age during which the Elgin Reptile lived. 

 Such a combination of characters as it presents would, I apprehend, 

 be in perfect keeping with the known Eeptilian Pauna of any epoch 

 from the Wealden downwards. 



Foot-jprints (PI. XIY. figs. 4 & 5). — I have intentionally deferred 

 to the end of my communication the description of the footmarks 

 which have been observed upon the sandstones of Cummingstone, 

 because, although they are certainly the tracks of Reptiles, there is, 

 strictly speaking, no proof whatsoever that they were produced by 

 the particular Reptile Stagonolepis, no fragment of which has been 

 detected in the Cummingstone quarries. It is desirable therefore 

 that the foot-marks should be considered quite independently, though 

 it may be instructive to inquire what positive and negative evidence 

 there is in favour of thinking them to be the work of Stagonolepis. 



Although a considerable series of these tracks has passed under 

 my inspection, I have only seen two foot-marks which are so clear 

 and distinct as to satisfy mj mind that they fairly represented the 

 figure of the foot. The two impressions in question form part of a 

 continuous track, evidently made by the same animal, and exhibiting 

 three pairs of right-foot prints (of the fore and hind foot on each 

 side) and two pairs of left-foot prints. 



(Fore Foot.) — The most distinct impression of the anterior foot 

 (fig. 4) is the middle one of the three on the right side. Its greatest 

 breadth is 2|- inches, its greatest length 3-| inches. The plantar 

 surface of the foot measures 1^ inch in its greatest antero -posterior 

 diameter. The impressions of five digits are visible ; and the proxi- 

 mal joints of the third digit, taken together, equal rather more than 

 an inch in length, while the impression of its terminal joint is 1| 

 inch in length. 



This plantar impression is on the whole transversely oval, its 

 anterior boundary presenting a tolerably even convexity forwards, 

 while the posterior boundary, equally, or more, convex backwards, 

 presents an emargination opposite the base of the middle digit. A 

 line drawn from the emargination to the base of the fourth digit 



