1. Purbeck Beds. 1. Coral Rag. 1. Cornbrash.
2. Portland Stone 2. Oxford Clay. 2. Great Oolite & Forest
and Sand. Marble.
3. Kimeridge Clay. 3. Stonesfield Slate.
4. Fuller’s Earth.
5. Inferior Oolite.
The alternations of clay and masses of limestone in the Liassic and
Oolite formations impart some marked features to the outline of the
scenery both of France and England: forming broad valleys, separated
from each other by ranges of limestone hills of more or less elevation.
In France, the Jura mountains are composed of the latter; in England,
the slopes of this formation are more gentle--the valleys are
intersected by brooks, and clothed with a rich vegetation; it forms what
is called a tame landscape, as compared with the wilder grandeur of the
Primary rocks--it pleases more than it surprises. It yields materials
also, more useful than some of the older formations, numerous quarries
being met with which furnish excellent building-materials, especially
around Bath, where the stone, when first quarried, is soft and easily
worked, but becomes harder on exposure to the air.
The annexed section (Fig. 109) will give some idea of the configuration
which the stratification assumes, such as may be observed in proceeding
from the north-west to the south-east, from Caermarthenshire to the
banks of the Ouse.