ON THE EROSION OF THE SHORES OF THE SEVERN ESTUARY. 207 
The southern part of this alluvial area is protected by a wall, at the 
southern end of which the river impinges, causing great erosion of the 
adjacent Lias cliffs and necessitating further a recent renewal of 
part of the wall. 
5 . — From Garden Cliff, near Newnham, to the Mouth of the Wye. 
We now pass to the western side of the Severn estuary. Much 
of the base of Garden cliff is directly washed by the Severn, and is 
being considerably eroded ; the general freedom of the western part 
of the cliff from vegetation is further evidence of the wear to which 
it is subjected. When the lower part of the cliff is formed of the Red 
Keuper marls the erosion is uniform ; when the Rhaetic comes down 
to near the water level the hard bands, and especially the Pullastra 
sandstone, are strongly undercut. There is some erosion of the Red 
Keuper marls to the north and south of Newnham, but with the 
bend of the river at Aure an area of alluvium comes on which 
continues to be added to. 
For a distance of about two miles to the north and a similar 
distance to the south of Severn Bridge Station the Severn is bounded 
by a cliff of Old Red Sandstone which is a good deal overgrown, 
and is separated from the river by the Severn and Wye Railway ; 
there is clearly no fluvio-marine erosion in progress here. From 
Nass Cliff, near Lydney, as far as the neighbourhood of Tidenham, the 
coast is formed of alluvium. From near Tidenham to the northern 
end of Sedbury cliff the coast is bounded by a low cliff of Red 
Marl, and here the erosion is certainly very considerable. The cliff is 
vertical, has no protecting talus at the base, and the projecting roots 
of trees or sometimes whole trees detached from the cliff show how 
rapid the erosion is. For a short distance near the northern end a 
soft band of the Keuper comes down to high water mark and is 
very much undercut, narrow openings penetrating the cliff for as 
far back as twelve feet at least. At Sedbury Cliff the Red marl is 
overlain by the Grey marl, Rhaetic and Lower Lias, and here as at 
the opposite Aust Cliff the retirement of the cliff is more due to the 
ordinary subaerial agents than to the river. Numerous small slips 
obscure the base of the cliff, and it is further protected by a talus 
of blocks from the hard bands of the Rhaetic and Lower Lias. For 
about half-a-mile to the south of Sedbury Cliff the shore is bounded 
by a strip of alluvium, and then from the Three Salmon ” to the 
landing stage it consists of Red marl showing the same rapid 
erosion as in the area to the north of Sedbury Cliff. 
Beachley Point owes its existence to the occurrence of a mass of 
Carboniferous limestone, which is seen not only at the Point, but 
practically all along the Eastern coast up to the landing stage. It 
is overlain unconformably by the Red marl which, as a rule, does 
not come down to the shore line. In the Geological Survey map no 
Carboniferous limestone is shown on the east coast of the promontory, 
and the relation of the Carboniferous limestone to the Trias is repre- 
sented as a faulted junction. 
