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1848. | WESTON ON THE GEOLOGY OF RIDGWAY. 253 
The dip of the Purbeck and its underlying Portland oolite is clearly 
exhibited by the railway cuttings, and we can see distinctly that the 
Purbeck beds do not lie in a basin or trough of Portland stone, as 
was supposed, but that they rest conformably upon it, and that both 
formations dip regularly to the north in their natural order under 
the Hastings sand. The dip increases from the base of the Portland 
stone to the top of the Purbeck; south of (m) in section Fig. 1, ranging 
about 30°, and on the north side about 45°. 
The Purbeck and Portland beds have been subjected to great ele- 
vations and depressions in the locality under consideration, and as 
these disturbances are evidently connected with the singular position 
of the strata overlying them, it may be desirable now to consider 
these phenomena more particularly. 
Near the cutting in which we find the Hastings sands and Oxford 
clay a gradual depression of the surface-line is perceptible, sinking 
more rapidly on the east near the farm-house. This depression I do 
not consider as merely external, but as essentially connected with the 
stratification below. We therefore find the different quarries on the 
hill presenting different inclinations, some dipping to the north and 
others to the south. This variation is even seen in contiguous 
quarries. 
There is one quarry on the west of the cutting, and not very far 
from it, which dips to the east,—that is, towards the vertical strata, 
leading us to infer that the cause affecting both was a common one. 
On the same range, further west, there is another quarry (A.), 
South. Fig = 2 Ridgway Range. 
y: North. 
e. Chalk. d, Portland. e. Purbeck, 
Fig. 2, in which the Purbeck formation presents the following strata, 
all dipping to the south :— 
Gravel and large rubble. 
Fibrous carbonate of lime. 
Ribbon-like deposit of Purbeck stone. 
Fibrous carbonate of lime. 
Blue clay, containing what appeared to be small Ostree. 
Blue, hard Purbeck marble. 
Blue fibrous carbonate of lime. 
Blue clay. 
Stone. 
Schistose stone. 
Blue band. 
Stone. 
Schistose stone with ripple water-mark. 
