432 Report of the Progress of the Sciences in France. 
neralogists, the Thuringewald, and Braun Neergard has given, 
us an account of their journey. In similar researches we 
ought chiefly to mark out the chains of primitive earths which 
traverse the surface of the globe. I have distinguished for in- 
stance five great masses of primitive earths in France : 
1. A portion of the Alps. 
2. The Cevennes. ; 
3. A porticn of the Pyrenees. 
A. The mountains of Bretagne. 
5. The Vosges. 
Secondary Earths. —On this subject Risso has given a de» 
“scription of the caleareous earths in the vicinity of Nice. All 
these secondary earths contain quantities more or less consr~ 
derable, of fossils, 2. e. traces of animals and vegetables. 
The knowledge of fossils may afford some notions as to the 
formation of the strata of the globe in latter times: this branch 
of geology, therefore, is making rapid progress, as we are better 
acquainted with living animals and vegetables. J have distin- 
guished three fossil orders : 
Marine fossils deposited at the bottom of the sea. 
Fresh-water fossils deposited in fresh water. 
Land fossils deposited in the bowels of the earth, or buried by 
the fall of mountains, without having been touched by water. 
We can also distinguish ‘ 
The fossils of organized beings which live in the ocean. 
The fossils of organized beings which live in fresh water. 
The fossils of organized beings which live on the continents. 
FRESH-WATER STRATIFICATIONS. 
It cannot be doubted that there were strata formed in fresh- 
water lakes after the lowering of the level of the water of the 
ocean, as I have proved in my Theory of the Earth, tome v. 
137. 
3 Lamanon long since recognised fresh-water shells in the strata 
of the environs of Paris; which made him say that several of these 
strata, and particularly the chalks, were formed in fresh-water 
lakes. He has said the same of the chalks of Aix in Provence. 
Coupé has also given accurate descriptions of the soils in the 
environs of Paris: he there recognised fresh-water shells. 
Cuvier and Brongniart have adopted the opinion of Lamanou 
with respect to certain soils in the environs of Paris. They sup- 
pose that they have been formed in fresh water, hecause fresh- 
water shells are there found. They found at Montmartre a cy- 
olustome of a blackish colour. 
Brongniart, Prevost, and Desmaret jun. also observed fresh- 
water shells in part of ‘Auvergne. Bendaut has also found /ym- 
nee (fresh-water shells) near Vaucluse. ‘They have also pepe 
2 oun 
