440 
the localities above enumerated, many of the shells, which in several 
places in Touraine are beautifully preserved, occur only as casts. 
Rennes.—The country between Dinan and Rennes consists of an- 
cient rocks. M. Desnoyers states, in the memoir before alluded to, 
that tertiary beds of the age of the Paris basin and of the Faluns 
eecur near Rennes, but Mr. Lyell is not aware of any published ac- 
count of the fossils. In the ancient quarries of St. Gregoire, to 
which he was conducted by M. Pontallier, he found corals and easts 
of shells of Touraine species; also a large Spatangus, a claw of a 
crab, and teeth of sharks, imbedded in soft and hard hmestones 
similar to those near Dinan. At La Chaussairie, five miles south of 
Rennes, oceurs a perfectly distinct limestone, containing Milliolites 
and casts of marine shells, resembling those of the Paris basin; and. 
associated with it are green and blue marls, enclosing freshwater 
Testacea. The deposit is of small extent, and rests upon transition 
strata; but Mr. Lyell suspects that it is m places overlaid by the 
ruins of the true Faluns, and that from these were derived the re- 
mains of a Lamantin and a tooth of Carcharias megalodon, found in 
the debris of a shaft sunk at La Chaussairie. 
Nantes.—The district between Rennes and Nantes consists of 
transition and granitic rocks, but there are many detached patches of 
Miocene strata around Nantes. At Les Cleons ts a soft coralline 
limestone, containing pebbles of quartz and spangles of mica, the 
fundamental rock of the country being mica-schist. Mr. Lyell ob- 
tained from the limestone six species of corals and five of 'Testacea, 
the whole of which, capable of determination, belong to Touraine 
fossils. In the museum at Nantes he saw specimens which indicate 
the existence of Falun strata’ at Le Loroux, Vieilleville and Limousi- 
niere, places within thirty miles of Nantes; also other organic re- 
mains which prove that Eocene strata occur at Cambon. 
Angers.—Mr. Lyell was prevented from examining the pits north 
of this place, but he was presented by M. Millet with an extensive 
suite of shells and corals, collected by that gentleman. Of fifty- 
seven species of Testacea, all but thirteen occur in the Faluns near 
Tours, Savigné and Pontlevoy ; but the fact of there being thirteen 
peculiar to the Angers district induces Mr. Lyell to suspect that the 
fossils depart more than those of other localities from the common 
type. The collection contains also only nine species which can be 
positively identified with known recent shells, and one which is 
doubtful, giving about seventeen per cent. of existing species, a much 
smaller proportion than was obtained by the author in other localities. 
Doué.—At this town are extensive quarries of a calcareous build- 
ing-stone, composed of comminuted shells and corals, and exposed 
to the depth of forty feet. The beds are horizontal, but exhibit 
highly inclined cross-stratification. From the marl-beds at La Gré- — 
zille, and the calcareous sand and limestone of Renaudan and Tllet, 
villages situated six or seven miles north of Doué, Mr. Lyell pro- 
cured twenty-four species of corals, four of Echinodermata and three 
of fishes ; also a few species of shells, the most conspicuous bemg the 
large Pecten solarium. In the great abundance of corals and Echi- 
