184 REMARKS ON CLASSIFICATION. [Ch. XV 



In support of this classification I pointed out the fact that the " upper 

 marine sands," or Gres de Fontainebleau of the Parisian series, with their 

 characteristic shells, extend southwards from the French metropolis, as 

 far as Etampes, which is within seventy miles of Pontlevoy, near Blois, 

 and not more than 100 miles from Savigne, near Tours, two localities 

 where the falunian shells are very abundant. So remarkable a difference 

 between the species of the valley of the Loire and those of the valley 

 of the Seine cannot be the result of geographical distribution at one 

 and the same former era, but must evidently have depended on a differ- 

 ence in the age of the deposits. It marks the influence of Time, and 

 not of Space. 



Another reason which induced me to class the Gres de Fontainebleau 

 and strata of the same age with the older series rather than with the 

 newer, was the decidedly Eocene aspect of the testaceous fauna, and the 

 fact that a certain proportion of the shells of the " upper sands" are' of 

 species common to the underlying Parisian strata. 



A different arrangement, however, was adopted by MM. Dufrenoy and 

 E. de Beaumont, in their coloring of the Government Map of France, for 

 they comprehended in their Miocene group, not only the faluns of Tou- 

 raine, but also the freshwater " calcaire de la Beauce," and the marine 

 sands and sandstone (Gres de Fontainebleau), i. e. all the tertiary de- 

 posits which lie above the gypseous series of Montmartre, a formation 

 well known as rich in extinct mammalia, first brought to light by the 

 genius of Cuvier. M. D'Archiac, in 1839, followed the same mode of 

 classification, dividing what he termed " Lower" from his " Middle ter- 

 tiary" in the same way. M. Deshayes, in his work on the Fossil Shells 

 of the Environs of Paris (1824-1837), had given twenty-nine species 

 as belonging to the upper marine strata, nearly all of which he distin- 

 guished specifically from shells of the Calcaire Grossier, although he 

 regarded them as characteristic of the same fauna. The railway cut- 

 tings near Etampes, in 1849, enabled M. Hebert to raise the number to 

 ninety, and he first pointed out that most of them agreed specifically 

 with shells of Kleyn Spawen, near Maestricht, in Belgium, and with 

 those of Rupelmonde and other places near Antwerp. These Belgian 

 fossils had been described by MM. Nyst, De Koninck, and Bosquet, and 

 their geological position had been accurately ascertained by M. Dumont, 

 and placed by him above the Brussels tertiary beds, which are the un- 

 doubted representatives of the Calcaire Grossier of Paris, a typical 

 Eocene group. M. de Koninck, about the same time, remarked that 

 the Kleyn Spawen, or " Limburg" fossils, were in part identical with 

 those of the Mayence tertiary basin, a group which in my first editions 

 I had assigned to the Miocene period. M. Beyrich more recently (1850) 

 has described a formation of the same age as that of Kleyn Spawen, 

 occurring within seven miles of the gates of Berlin, near the village of 

 Hermsdorf; and has shown that about a third of the species agreed 

 with known Belgian shells of the age of the Gres de Fontainebleau, 

 while about a fifth are English and French Middle Eocene species. 



