304 



AMERICAN TESTUDINATA. 



Part II. 



these footprints " were not made by a Cbelonian Reptile,^ nor by any vertebrated 

 animal." About the same time, Captain Lambert Brickenden^ described foot-tracks 

 fi'om the Old red sandstone of Morayshire, which are also ascribed to Chelonians. 

 Though I have not seen these fossil footprints, I have seen the impressions left 

 by Turtles, upon soft mud, often enough to feel justified in saying that the Scotch 

 footrmarks have not the remotest resemblance to the footprints of a Cbelonian. 

 These animals, when walking, stretch the legs on opposite sides of the body, in 

 a diagonal position with reference to the Ijody itself, so that the foot-marks of 

 the fore foot of one side and those of the hind foot of the opposite side, form 

 couples which alternate with the corresponding couples arising from the fore 

 foot and the hind foot of the other side. No such succession is observed in the 

 footprints described l)y Captain Brickenden. No more do the footprints from 

 the Red sandstone near Dumfi'ies, in Scotland, described by Dr. Duncan and by 

 Dr. Buckland, and reproduced by the latter in his Bridgewater Treatise, resemble 

 foot-marks of Turtles. 



Long before the publication of these difiei'ent notices, the existence of Turtles 

 in older geological formations had been asserted by Sedgwick and Murchison,^ who, 

 upon the authority of Cuvier, had referred to the genus Trionyx a fragment of 

 bone found in Scotland, in the slates of Caithness, which l^elong to the Old red 

 sandstone formation. These remains I have shown, in my work on Fossil Fishes,* 

 to be those of a very remarkable type of extinct Fishes, forming a distinct 

 familjr, the Cej)halaspides, and beloiaging to the genus Coccosteus. Kutorga has 

 also described fragments of iish bones of the Old red sandstone, as belonging to 

 the ftimily of Trionyx.^ In his researches on fossil bones, Cuvier, finally, has 

 referred to Chelonians several remains from the Muschelkalk, which were after- 

 wards shown by Herman von Meyer to belong to the genus Nothosaurus. 



These are, as for as I know, all the instances in which the existence of Turtles 

 in deposits older than the Jura has been maintained. Though introduced by the 

 highest scientific authorities, there is not one of these alleged cases which stands 

 a careful criticism. Neither the tracks of the Potsdam sandstone of Owen, nor 



^ Description of the Impressions of Footprints of 

 tlie Protichnitis from the Potsdam Sandstone of Can- 

 ada, by Professor Owen, Quarterly Journal of the 

 Geological Society of London, 1852, vol. 8, p. 214. 

 The geological description of Sir "William Logan, 

 which precedes, p. 199, gives the most minute account 

 of the occurrence of these fossil footprints in Canada. 



- Quarterly Journal of the Geological Society of 

 London, vol. 8, p. 97. 



^ On the Structure and Relations of the Deposits 

 contained between the Primary Rocks, and the Oolitic 

 Series in North Scotland, by A. Sedgwick and R. I. 

 Murchison, in the Transactions of the Geological So- 

 ciety of London, 2d series, vol. 3. 



* Monographic des poissons fossiles du vieux Gres 

 Rouge, Neuchatel, 1844, 1 vol. 4to. p. 22. 



^ See the same Monograph, p. 91. These re- 

 mains belong to the genus Asterolejiis. 



