Ch. XVI.] FOSSIL FOOTPRINTS. 301 



It was easy to throw discredit upon the new doctrine by asking 

 whether corals, shells, and other creatures previously unknown, were 

 not annually discovered ? and whether living forms corresponding with 

 the fossils might not yet be dredged up from seas hitherto unexamined ? 

 But from the era of the publication of Cuvier's " Ossements Fossiles," 

 and still more his popular Treatise called " A Theory of the Earth," 

 sounder views began to prevail. It was clearly demonstrated that 

 most of the mammalia found in the gypsum of Montmartre differed 

 even generically from any now known to exist, and the extreme improba- 

 bility that any of them, especially the larger ones, would ever be found 

 surviving in continents yet unexplored, was made manifest. Moreover, 

 the non-admixture of a single living species in the midst of so rich a 

 fossil fauna was a striking proof that there had existed in that 

 region a state of the earth's surface zoologically unconnected with the 

 present. 



Fossil footprints. — There are three superimposed masses of gypsum 

 in the neighborhood of Paris, separated by intervening deposits of 

 laminated marl. In the uppermost of the three in the valley of Mont- 

 morency M. Desnoyers discovered in 1859 many footprints of animals 

 occurring at no less than six different levels.* The gypsum to which 

 they belong varies from thirty to fifty feet in thickness, and is that 

 which has yielded to the naturalist the largest number of bones and 

 skeletons of mammalia, birds, and reptiles. I visited the quarries, 

 soon after the discovery was made known, with M. Desnoyers, who 

 also showed me large slabs in the Museum at Paris, where, on the up- 

 per planes of stratification, the indented footmarks were seen, while 

 corresponding casts in relief appeared on the lower surfaces of the 

 strata of gypsum which were immediately superimposed. A thin film 

 of marl, which before it was dried and condensed by pressure must 

 have represented a much thicker layer of soft mud, intervened be- 

 tween the beds of solid gypsum. On this mud the animals had 

 trodden, and made impressions which had penetrated to the gypseous 

 mass below, then evidently unconsolidated. Tracks of the Anoplo- 

 therium with its bisulcate hoof, and the trilobed footprints of Paleo- 

 therium, were seen of different sizes, corresponding to those of several 

 species of these genera which Cuvier had reconstructed, while in the 

 the same beds were footmarks of carnivorous mammalia. The tracks 

 also of fluviatile, lacustrine, and terrestrial tortoises {Emys, Trionyx, 

 &c.), have been discovered, also those of crocodiles, iguanas, geckos, 

 and great batrachians, and the footprints of a huge bird, apparently a 

 wader, of the size of the gastornis, to be mentioned in the sequel. 

 There were likewise impressions of the feet of other creatures, some 

 of them clearly distinguishable from any of the fifty extinct types of 

 mammalia, of which the bones have been found in the Paris gypsum. 



* Sur des Empreintes de Pas d'Animaux, par M. J. Desnoyers. Cornpte Rendu 

 de l'Institut, 1859. 



