MIOCENE FOSSILS. 



cerne these beds consist of a coarse conglomerate, called " nagel- 

 fiuhe," passing into a finer sandstone (the " molasse" of French 

 geologists), which is usually soft and incoherent, but sometimes 

 sufficiently hard to be used as a building stone. Various beds of 

 lignite and marl are irregularly distributed through the moiasse, 

 which are evidently of fresh- water origin. 



20. The marine deposits of the miocene strata, although abound- 

 ing in shells, do not contain as great a number of species 03 the 

 marine limestone of the Paris basin; yet, eighteen per cent, of 

 these species are identical with those now Jiving in the neighbour- 

 ing seas. There is often the strongest analogy between these new 

 deposits and the lower limestones, with which they have been 

 confounded ; yet, if we do frequently observe a common aspect, 

 and often find the same shells in both, there is, nevertheless, es- 

 sential differences between them. In one case, we no longer find 

 species characteristic of the lower deposits ; there is no ceri'thium 

 giga'nteum, no car'dium porulo'sum, &c. : in the other, we find 

 new remains which we did not meet with before, such as the 

 Bala'nus cra'sus (Jig. 161), the Rostella'riapespelica'ni (fig. 102), 

 the Pe'clen pleurone'ctes (fig. 163), &c., which are never found in 

 the Paris basin, but exist in the subapennine formation. 



Fig. 161. Bala'- 

 nus crasus. 



Fig. lK2.Rostella'ria 

 pespelica'ni. 



Fig. 163. Pe'cten 

 pleurone'ctes. 



21. The strata belonging to this period of the tertiary formation 

 contain divers species of paleothe'rium, but differing from those 

 found in the Paris gypsum. Here we also find several other species 

 of animals, which constitute genera, no trace of which is met with 

 in the preceding formation, and which totally disappear in the suc- 

 ceeding epoch. Here we find the remains of ma'stodons (from 

 the Greek, mastos, a nipple, and odous, tooth), animals analogous 



20. What is the character of the fossils of these beds? What proportion 

 of them resemble recent or living species ? 

 8 



