438 
Lyell examined in the summer of 1840, first, certain of the newer 
tertiary deposits in La Manche, particularly those near Valognes, 
and: between Carentan and Coutances; then the tertiary strata in the 
neighbourhood of Dinan and Rennes; and afterwards those along 
the course of the Loire from Nantes to Tours and Blois, extending 
his researches northwards of that river as far as Savigné, and south- 
wards to Bossée and Pontlevoy. ‘The following notices contain sum- 
maries of the observations made at each locality. 
Crag. 
Tertiary strata near Valognes.—The first geologist who explored 
the Cotentin was M. De Gerville. M. Desnoyers, m his memoir on 
that part of Normandy (published in 1825), shows that the newest 
secondary rock near Valognes is Baculite limestone*, and that it is 
overlaid by patches of tertiary strata, of the age of the Paris basin ; but 
he does not allude to any deposit of more recent date. By the advice 
of M. De Gerville, Mr. Lyell visited a marl-pit at the farm of Cadet, 
near Ranville la Place, eight miles south-west of Valognes, and he 
found it to abound with Suffolk crag shells. He obtained twenty- 
nine species of Testacea, fifteen of which Mr. Searles Wood has 
identified distinctly with crag species, and seven doubtfully, the 
most abundant shell being Lucina radula. In M. De Gerville’s col- 
lection from this locality, Mr. Lyell saw a specimen of the Falun va- 
riety of the Voluta Lamberti, or of what he considers to be a distinct 
species of Voluta. It is stated to haye been found under an oyster- 
bed, and beneath the stratum containing the above shells. 
Carentan.—At St. George de Bohon, five miles south-west of Ca- 
rentan, is another deposit of Suffolk crag fossils. -In travelling south 
from Carentan this formation is first met with at the hamlet of La 
Flaget. It consists of an iron-stained calcareous tufa, or an agere- 
gate of fragments of organic remains, and is in some places thirty 
feet thick. The shells are dificult to extract, but Mr. Lyell ob- 
tained fourteen species; also three species of corals, and a caudal 
tubercle of a Raia, all of which haye been identified with Suffolk crag 
fossils. Among the shells are numerous fragments of the large 
Terebratula variabilis. The corals and some of the Testacea are com- » 
mon to the Faluns of Touraine, but none of the distinguishing fossils 
of the latter have been discovered in the Carentan deposits. : 
Sainteny.—In sinking a well at this place, more than sixty feet of 
a white calcareous aggregate of comminuted shells were passed 
through. At Longueville, one and a half mile from Sainteny, is a 
soft caleareous stone, consisting of innumerable casts of fragments 
of shells, among which Mr. Lyell detected the Pecten striatus of the 
Suffolk crag; and a similar rock occurs at the farms of Blehou and 
Raffanville, several miles distant. The fossils obtained. at these lo- 
calities could not be satisfactorily determined, but Mr. Lyell is of 
* Mr. Lyell examined this limestone, and recognised its resemblance to 
the uppermost chalk at Faxoein Seeland. See ‘ Proceedings,’ vol. ii. p. 191,_ 
and ‘ Geol. Trans.,’ 2nd Series, vol. v. p. 248, for an account of the Faxoe 
deposit, 
