114 Rh. M. Deeley—The Thames Valley Gravels. 
Before we can consider the question of the high-level gravels of 
the Thames Valley as being in any way properly dealt with, it is 
necessary to get as clear a view as possible of the movements of the 
ice-sheets which invaded this area. This is a difficult matter to 
accomplish, for British geologists have generally confined themselves 
to considering the greatest area which can be shown to have been 
covered by ice and the directions in which it probably travelled ; but. 
the trend of the rock striz and the variable nature of the deposits in 
some areas show that the direction of the flow changed very con- 
siderably from time to time, as also did the areas covered by the 
ice at different times during what seems to have been the same epoch 
of glaciation. 
One of the most interesting ice-flows is that which passed over the 
Stainmoor Pass and carried with it the well-known Shap granite. 
That at one time this ice-flow passed in an easterly direction out into 
the North Sea is shown by the occurrence of this rock at Elwick, as 
far north as Hartlepool. This uninterrupted movement of the 
Stainmoor ice to the east was also shared by that coming through the 
Tyne Gap.’ Trechmann shows that the ice from Scandinavia 
pressed against the English coast between these two lobes. 
Subsequently the ice from the Cheviots was deflected in a southerly 
direction by this North Sea ice and passed down the coast. It 
has generally been considered that this deflection of the British 
ice-flows was only due to the advancing Scandinavian ice, but it may 
have been partly due to the waning of the British ice-sheets as the 
Scandinavian ice advanced and thickened. 
Lamplugh*? shows that further south at Flamborough Head 
similar changes in the direction of the flow took place, the Basement. 
Clay of Holderness being the oldest and having a Scandinavian origin, 
whilst the subsequent flow was down the coast. This alteration in 
the direction of the ice-flow becomes more marked as we reach Central 
and Western England. In the Trent Valley this change in the 
direction of ice-flow is very pronounced. Deeley * has shown that in 
this area the ice first came from the west, and that its fluvio-glacial 
gravels and sands went as far east as Grantham. Subsequently this 
ice-flow melted away and its place was taken by the ‘‘ Northern ”’ 
ice-flow which laid down the Chalky Boulder-clay. One lobe of this. 
flow turned towards the west and passed up the Trent Valley, laying 
down upon the older boulder-clays and fluvio-glacial deposits the 
Chalky Boulder-clay and its fluvio-glacial deposits. The ice from 
the west and that which came down the Derwent Valley advanced 
into a submerged country, a submergence probably due to the 
presence of the Scandinavian and Scotch ice in the North Sea. 
Associated with the hard till with glaciated boulders formed by the 
early western and Pennine ice, are clean current-bedded sands and 
eravels not containing flints, and sedimentary clays containing well- 
glaciated boulders, but no flint. 
That this ice-sheet was very thick in the Irish Sea is shown by the 
1 Q.J.G.S., vol. lxxi, pp. 538-80, 1915. 
2 Q.J.G.S., vol. xlvii, pp. 384-429, 1891. 
3 Q.J.G.S., vol. xlii, pp. 437-79, 1886. 
