VOL. XIV. (3) | THE PRESIDENT’S ADDRESS 187 
the Bromwich Hill gravel, and now in the Museum, is 
perfectly unworn. South of Worcester, Salopian detritus 
becomes less abundant. At Kempsey, five miles to the 
south, in a good section of sand and gravel, the base of 
which is between 40 and 50 feet above sea-level, I found 
pebbles of Wrekin rhyolite, Uriconian volcanic grit, 
Eskdale and other granites, and a grey felsite, which may 
have come from the Arenigs, by way of Shropshire. Mr 
Richardson has also detected a fragment of typical rhyolite 
from the Wrekin as far south as Limbury Hill, five miles 
north-west of Gloucester. 
I have now shown you that our southern gravel is 
largely derived from Shropshire, that the marine shells 
contained in it are identical with species which occur in 
gravel and sand on or near the banks of the Severn at 
Shrewsbury and Buildwas, and that these shells are much 
_ water-worn. We may infer with reasonable certainty that 
the marine shells in our Southern Drift are derived from 
Salopian gravels, and were transported to their present 
position by the river itself. It is, therefore, obvious that 
they do not prove the former presence of the sea in the 
lower Severn valley. 
Murchison supported the evidence of the marine shells 
by considerations derived from the physical features of 
the district. Heclaims a marine origin for the Cotteswold 
escarpment. He refers to what he describes as its 
“salient and re-entering angles, precisely like the head- 
lands of a shore, formed by the action of a sea acting upon 
hard and soft materials.” When he wrote these words, 
the comparative effects of marine and sub-aerial denudation 
had not been adequately studied. The facts do not 
support his hypothesis. The projections of the escarp- 
ment are not composed of harder materials than the 
recesses. The strata forming the eastern rim of the valley 
are of approximately uniform composition from end to 
