HOW SCENERY IS MADE 
43 
when deposited at the bottom of the sea, when it arose and 
became land the rain, after centuries of work, has cut away 
extensive areas, wherever the first formed rills found their way 
down, forming brooks and finally rivers. Hence a clay country 
has no very marked features, being often fiat, as about Cambridge 
and Ely, or undulating as in Suffolk and Norfolk and the valley 
of the Severn. 
A feature due to “ denudation ” of cliffs by the sea-waves is 
seen along our coasts in the form of “ outliers,” i.e., columns of 
rock isolated from the mainland. Thus the chalk “ Needles” at 
the west end of the Isle of Wight were formerly united to the 
cliffs at Studland Bay on the west, before the sea broke down the 
barrier and so made the Solent. 
Now if we follow the line of the Cotswold Hills from, say, 
Stroud to Rockingham, we find similar but much larger outliers 
in abundance all the way through Gloucestershire, Oxfordshire, 
and Northamptonshire, with numerous river- valleys having the 
same limestone for their sides, but the Lias clay at the bottom 
for the river-beds. There is one of these outliers so far west 
as near Upton on Severn, showing that the whole of the Severn 
valley was once covered with the same yellow limestone as may 
be seen at the Leckhampton Hills by Cheltenham, which stands 
on the Lias clay. 
With regard to the characters of clay : — when it becomes 
hardened by pressure, it splits into flat fragments called “shale.” 
If you happen to be near a coal-mine, you may see great 
quantities thrown out into heaps by the pit’s mouth, often 
having impressions of ferns upon them. This was the clay 
in which the plants grew, as well as rhat which was thrown 
down upon the plants and buried them, now forming the “ roofs ” 
of the seams of coal. 
But the finest scenery in the world is the result of clay-mud 
after it has gone through the process of hardening, by pressure 
and heat, when it becomes slate, and has undergone great 
terrestrial upheavals, so that what was at first horizontal may 
become even vertical. 
The peculiar way in which slate rocks split causes the rocks 
to become pointed and jagged, whence the word “ dent ” or 
tooth, so frequently applied to mountain tops in Switzerland, as 
around Mount Blanc. 
The slate rocks being excessively hard are not worn down 
either by “weathering” or decomposition, as even granite can 
be : they split, however, into rhomboidal or lozenge- shaped 
masses, and these, loosened by frost, fall out. This result in 
the Swiss mountains is very marked, for these depressions 
give opportunity for snow to accumulate in the higher regions, 
forming the so-called “ couloirs ” or basins wherein the great 
glaciers take their rise. 
The chief mechanical use of slate is for roofing purposes. 
The possibility of this resides in the property of “ cleavage.” 
