888 The Geological Survey of 'England and Wales. 
Catworth has been built on it, and it extends also over a considerable 
area of the surrounding land. 
While alluding to the older drifts of the South of England, I may 
refer to the fact that the recent extension of the Geological Survey 
into South Wales, for the revision of the coalfield, has enabled us to 
begin the systematic examination cf the superficial deposits of that 
region, which up to the present time are almost unknown. Mr. A. 
Strahan has found true ice-striated rock-surfaces and undoubted 
Boulder Clay, indicating a southward movement of the ice, together 
with abundant deposits of sands and gravels which are probably 
the most southerly examples of true eslcers or kames in this 
country. 
Much attention has been given by the officers of the Survey to 
the mapping of the high-lying or plateau-gravels in the Isle of 
Wight. Much of this island, as well as of the low grounds of 
Hampshire, has been shown to have been formerly overspread by 
these deposits ; but they exist now only in widely separated patches, 
which, lying high above the modern valleys, serve to mark the great 
denudation undergone by the island. A more recent set of river 
gravels, distributed along the existing valleys, has obviously been 
derived from the waste of the plateau -gravels. By the encroach- 
ment of the sea the valley of the West Yar has been cut across, so 
that the valley-gravels now form a capping to the sea cliff. In the 
Weymouth district Mr. Strahan has recently mapped some interest- 
ing tracts of high-level gravels, which have been deeply denuded, 
and from which possibly the materials of the famous Chesil Beach 
may have been in part derived. 
The mapping of the southern portions of Sussex by Mr. Clement 
Reid has brought to light several novel and important facts in 
regard to the condition of that part of England during the Ice Age. 
He has discovered that a deposit with glacially striated erratics lies 
there beneath certain clays full of the remains of temperate animals 
and plants, whilst above these clays comes another deposit produced 
apparently under arctic conditions. 
Tertiary . — The re-examination of the Tertiary areas to the west 
of London for the Drift Survey lias shown the general accuracy of 
the old mapping, though the boundary lines have been occasionally 
improved. In Hampshire and the Isle of Wight more extensive 
alterations have been necessary. Thus, the Hamstead Beds, in 
place of occupying mere isolated patches on the high ground, as was 
believed when the original map was prepared, are now known to 
cover a large area. This was proved by Mr. Reid, chiefly by the 
use of portable boring-rods, such as had for some time previously 
been employed by the Belgian Geological Survey. These tools have 
also proved of great service in some recent work in the Eastern 
Counties. Certain small outliers on the Chalk of Hampshire, shown 
as Eocene on the old map, have now been placed among the drifts, 
and have been mapped as “ Clay- with- flints.” Probably here, as is 
often the case in parts of the London Basin, the so-called “ Clay- 
grith-fjints ” is in great part rearranged Eocene material. 
