250 w. A. E. USSHER ON THE TRIASSIC 
(apparently a redistribution of the Trias) is overlain by coarse buff 
quartzose sand, with patches of bluish lead-coloured clay in places. 
The whole seems to attain a thickness little short of 100 feet. The 
clay may haye resulted from the destruction of Infraliassic outliers. 
On ascending the hill from St. Martin d’Audouville toward Octe- 
ville a similar dark-coloured clay is irregularly associated with sand 
and gravel, the whole being overlain by brownish earthy diluvium 
covering the high ground. These deposits appear to me to represent 
the Diluviwm gris and rouge respectively. : 
Toward Octeville, with the descent of the ground, a yellowish- 
brown quartzite gravel makes its appearance, being exposed near 
the village to a depth of 10 feet. Proceeding from Octeville (la 
Venelle) to Crasville, similar quartzite gravel associated with sand 
is exposed to a depth of 15 feet; on the further side of the valley 
the gravel is associated with buff sand, and seems to rest on the 
Paleozoic rocks which are exposed in quarries at Crasville and at 
about a quarter of a mile to the north of it. From the presence of 
an Infraliassic outlier at Octeville*, I regard these gravels, as well 
as those near St. Martin d’Audouville, as the uppermost beds of the 
Trias. 
By the road leading south-east from Octeville, within a quarter 
of a mile of the village, brown gravel, either Trias in situ or 
redeposited, overlies red and grey marl resting on whitish rock- 
sand, overlying, and apparently passing into, quartzite gravel in buff 
sand exposed in a pit to the depth of 10 feet. 
Quitting this read and following a by-lane leading southward, 
parallel to the stream (towards Lestre), Triassic rocks appear to be 
subjacent, faint indications of quartzite gravels and marl being some- 
times met with in the loamy drift-soil. By the road to Lestre, 
which crosses this stream, and at a point about 500 yards from the 
village, the Trias appears to be represented by coarse whitish sand- 
rock with occasional small pebbles and quartzite gravel. 
On the south-east of the village, by a semicircular by-lane, a 
quarry, 6 feet in depth, exposes irregular rubbly beds of greyish 
marlstone with carbonate of lime disseminated throughout; the rock 
seems to be quite devoid of fossils, and weathers in rugged corruga- 
tions. : 
This variety of the Trias appears to be very local, and not much 
to exceed the exposed 6 feet in thickness. 
It is mentioned by M. Bonissent, who described the Lias of Lestret, 
as follows :—‘‘ Here calcareous greyish quartzose sandstones appear 
under the Diluyium; they are often red or amaranthine in colour, 
micaceous, and more or less solid, sometimes friable: they rest on a 
compact limestone of violet, reddish, and yellowish hues. In some 
of these rocks, particularly where the calcareous element predomi- 
nates, little geodes lined with white crystals of carbonate of lime 
occur; the rocks are often full of cavities giving them the aspect of 
* “Ties petits ilots de Videcosville, Octeyille la Venelle et St. Germain-de- 
Tournebut voisins du massif de Valognes,”’ Bonissent, op. cit. p. 275. 
+ Bonissent, loc. cit. p. 267. 
