260 The Origin and Mode of Formation of the Vale of Wardour. 
the northern side, from the fine hill at Dinton, by the peaked-up 
elevation at Ridge, till we come to that wider expanse at Fonthill, 
the beauty of which no doubt caused it to be the scene of the 
fabulous extravagances of a Beckford. 
Within this inner range of hills there is a considerable breadth of 
Clayey ground, running continuously round the vale, the subdivisions 
of which I will allude to further on. 
So far we have been noticing strata which belong to the Creta- 
ceous Series, viz., the Chalk, the Upper Green Sand, the Gault, the 
Lower Green Sand, and the Wealden. 
Let us next look at the strata which are exposed within, viz., the 
Jurassic series, the Purbeck, the Portland, and the Kimeridge Clay. 
How did the present arrangement of these various formations 
come about ? 
All these beds were sedimentary deposits, and consequently were 
laid down horizontally, but now we do not find them preserving 
that flat position any longer, They have been tilted, some one way 
and some another. 
How and when was this caused ? 
The strata of the vale have been subjected on several occasions to 
earth movements from below. 
Towards the end of the Jurassic Period its sea became shallower 
and shallower, till in Purbeck times there was even dry land in the 
midst of freshwater lagoons. 
Then these Jurassic beds were gradually tilted towards the east, 
and for a long time remained subject to the wasting influence of 
atmospheric agencies, which, in connection with an easterly dip 
which had been already given to these beds, exposed on the surface 
the Purbeck, the Portland, and the Kimeridge Clay. 
Afterwards on these exposed eastward-sloping outcrops of the 
Jurassic beds the deposits of the wide-spreading Cretaceous sea were 
laid down, and gradually extended over them, covering in turn each 
lower formation, as the limits of the sea increased westwards. 
This overlap of the Cretaceous Series on to the Jurassic Series in 
the West of England is a point of the greatest interest, since it 
reveals to us the way in which that old sea gradually increased, 
