Geoscience Reference
In-Depth Information
FIG
151.
Generalised bedrock succession for the Severn Valley Region.
FIG
152.
The Variscan Unconformity spectacularly exposed at Woodhill Bay, Portishead.
The upper rocks are dolomitic conglomerates of Triassic age, resting upon the tilted
Lower Old Red Sandstones of the Devonian. (Copyright British Geological Survey)
The other landscape feature of Regional interest here is the valley system of the
River Severn and Bristol Channel. Figure 153 shows the extent of the Bristol Channel
Basin, outlined by the pre-New Red Sandstone unconformity and filled mainly with
New Red Sandstone sediment. This basin formed as an area of persistent downward
