439 
opinion that they agree with those which are found near St. George 
de Bohon, except that he observed no fragments of the Terebr -atula 
variabilis. As far as they can be identified, they consist of Suffolk 
crag species, and they do not appear to possess a character interme- 
diate between the Suffolk fauna and that of the Faluns. 
Mr. Lyell saw no recurrence of this crag further south, and the 
most northern point at which he noticed a deposit of the age of the 
Faluns of Touraine was near Dinan, sixty geographical miles to the 
south-east of Sainteny, the intermediate country consisting of ancient 
strata and crystalline rocks. 
Fatuns. 
_ Dinan.—M. Desnoyers does not describe the Falun near Dinan, 
although he alludes to it. The neighbourhood of Dinan is en- 
tirely composed of granitic rocks ; but at the village of Evran, situated: 
near a stream which flows into the Rance, seven miles south of Dinan, 
is a Small tertiary deposit, consisting of ten or twelve feet of white 
corallme and shelly sand, overlaid by a bed of stiff, reddish-brown 
clay, of very variable thickness. The great irregularities presented 
at the junction of the two strata, and the occasional projection of 
continuous layers of the sand into the clay, Mr. Lyell explains by 
supposing that the former at the time of its denudation, and _pre- 
yiously to the deposition of the clay, possessed a certain amount 
of hardness, which allowed of its being undermined. At the bottom 
of the sand occur large oysters, different from the common ‘Touraine 
species O. virginica ; and in the same quarries Mr. Lyell found many 
corals,. fragments of Echinodermata, sharks’ teeth, ribs of the Laman- 
tin, vertebre of a Delphinus, and a tooth of a Mastodon. Some 
of the bones were buried in a solid semi-crystalline limestone, in 
which casts of shelis are common. The formation occasionally 
assumes a concretionary or travertine structure: at Le Quiou it 
is micaceous, and splits into flags; and at the village of Pas de 
Hac some pinnacles of soft, white, calcareous aggregate present 
in the lower part fine examples of cross-stratification. At St. 
Juvat the variety of building-stone called La jauge, and com- 
posed of comminuted organic remains, resembles the deposit near 
Sainteny, but the occurrence of casts of cones and large Cypreee 
convinced Mr. Lyell that it must be assigned to the Faluns. It 
-is overlaid by a bed of clay of variable thickness, having been 
_ very irregularly denudated; and it is penetrated by cylindrical hol- 
lows, similar to the sand-pipes in the English chalk. From these 
localities Mr. Lyell obtained twenty-six species of shells, one Cir- 
riped, five species of Echinodermata, five of corals, and seven of 
fishes, besides the remains of Cetacea and Mammalia before men- 
tioned. The shells are for the most part identical with species found 
in the Faluns of Touraine; the whole of the corals are well- 
known ‘ouraine fossils; and the fishes, according to M. Agassiz, 
have been all found in the molasse of Switzerland, with the excep- 
tion of one species, Carcharias megatodon. In the solid limestones of 
2 Pa 
