262 
MR. PRESTWICH ON THE GEOLOGY OF THE DEPOSITS 
and freshwater shells together with the remains of mammalia. This deposit is iden- 
tical with that at Gentilly * * * § . The section of this part of the valley of the Seine may 
therefore be represented as in fig. 8f. 
M. Charles d’Orbigny has traced the high-level gravel of Charonne, with few inter- 
ruptions, as far as Join ville five miles east of Paris. It there caps a hill rising abruptly 
80 to 100 feet above the river, and contains a large and interesting series of land and 
freshwater shells associated with the remains of the Elephas primigenius and Rhinoceros 
tichorhinus. No flint implements are recorded from these gravels. 
The same features hold good throughout the course of the Seine and its tributaries. 
Brongniart, in his description of the Paris basin, observes that the drift (Terrain de 
transport) occupies two positions — one in the valleys, and another on plains considerably 
raised above the actual rivers. He seems to suggest for them different origins §. 
Higher up the course of the Seine this structure has been more specially noticed. 
M. Leymerie, in describing the country traversed by the upper part of this river and its 
tributaries, remarks that at the commencement of the valleys there is but little drift 
(Diluvium), but that some way down them “ the beds of drift (Terrain diluvien) exhibit 
a great extension, both horizontally (maximum four leagues), and also in a vertical 
direction (maximum sixty metres) above the ordinary level of the valley-waters” |j. In 
the neighbourhood of Troyes they form a plain eight miles in length and of five miles 
average breadth, and attain in places a height of from 120 to 180 feet or even more 
above the river, with a thickness of 10 to 12 feet, and contain teeth of Elephant, Deer, 
Horse, & c. At Nogent there is another expanse of gravel 10 feet thick, and 200 feet 
above the river. In the tributary valley of the Aube, M. Leymerie describes at Brienne 
a similar expanse of gravel five leagues long by three broad, and 130 feet above the 
river 
Of the lower part of the valley of the Seine we possess but few details**. The plain 
through which the river winds is covered irregularly with a coarse sandy gravel, abound- 
ing especially in large blocks of Meuliere, Calcaire grossier, and of other tertiary rocks ; 
* M. Charles d’Orbigxy in Bull, de la Soc. Geol. 2 e ser. vol. xii. p. 1295 (1855). The pit he described is 
now filled up, but several others are open beyond the outer Boulevards. My sections are taken from these. 
t One of the best plans of valley-gravels, well and carefully worked out, that I have seen, is the one 
executed by M. Trigeb for the Department of the Sarthe. The river Sarthe, which flows through palaeozoic 
rocks, has a gravel abounding with blocks of granite &c., whilst the Huisne, which joins the former river at Le 
Mans, contains nothing but tertiary debris. The extent of these old alluvia are well shown on this fine 
map. 
t For a list of these and a description of the section, see Bull, de la Soc. Geol. 2 e ser. vol. xvii. p. 66 (1859). 
(I have recently had reason to believe that these fossils may be from old pits on a lower level than those now 
worked. Owing to this uncertainty I omit the list of fossils I had at first given. — March 1864.) 
§ Description Geol. des Environs de Paris, edit. 1835, pp. 118 & 569. 
|| Statistique Geol. et Miner, du dep. de l’Aube, p. 99 (1846). M. Clement Mullet had also remarked that 
at Fresnoy a gravel from 22 to 26 feet thick occurred at a height of 100 to 130 feet above the river ; and a like 
arrangement exists at Pougy in the valley of the Aube. Bull, de la Soc. Ge'ol. de France, vol. xii. p. 116. 
IT Ibid. pp. 88, 90 to 92, 94. ** See De Senarmont’s ‘ Descrip. Geol. du dept, de Seine et Oise.’ 
