4S0 
ON THE SUPERFICIAL STRATA 
right it is in depth SO feet, and passes into blackish clayey 
earth, the upper part ochreous. Twelve yards farther, its 
upper portion passes into clayey till, and its under into very 
compact till ; colour almost black, without pebbles, and im- 
pervious, naturally dividing into rock-Hke fragments. 
Sp. 7. — Into this till the orange-coloured ochreous mat- 
ter passes horizontally, 1, 2, and S feet, in veins, which, 
commencing fths or fths of an inch in thickness, with well- 
defined edges, proceed in an angular or zigzag course, ta- 
pering to their extreme points. In dimensions, shape, and 
common direction, they correspond ; but their angles are 
- all dissimilar. 
Sp. 8. — A selection of pebbles from the knoll, including 
the varieties. There are no traversing veins or slips. Many 
of the stones are rolled spheroids, chiefly soft coarse sand- 
stone, of an earthy-brown colour ; and from six to twelve 
inches in diameter. Yet the interior features of this knoll 
are manifestly regular. 
Sp. 9. — Fine sand from the knoll. 
Sp. 10.^ — Sharp sand from the knoll, grains larger. 
The following sketches, taken on the spot, will serve to 
shew the general structure presented by the remainder of 
this section. The lines express the larger features, paral- 
lel to which the filmy aggregation of the materials is ar- 
ranged. Some of the pebbles are enveloped in a thin cal- 
careous crust, attaching those contiguous. 
Fig. 5. Near centre of section. 
a. Soil. 
5, Small gravel and ochre ; brown earth. 
c, Sand ; alternate layers, ferruginous. 
Small clean gravel. 
Sand and clayey sand. 
Large gravel. 
