R. M. Deeley—The Thames Valley Gravels. 115 
fact that one lobe of it passed over the gap in the Pennines near 
Buxton and distributed Scotch and Cumberland rocks on the high 
land above Tideswell. At Bakewell, well up the Derwent Valley, 
there is a good deposit of boulder-clay formed by this ice. The 
graye-yard stands on it, and heaps of foreign erratics ure to be seen 
there. Another thick deposit of it is to be seen at Crich, where it 
rests upon a well-glaciated floor of Carboniferous Limestone. So 
thick was this ice in the Irish Sea, that it completely submerged 
Snaefell in the Isle of Man, which is 2,034 feet high. Coming from 
Cumberland and Scotland one lobe of it passed to the east of Wales 
into the Severn Valley. Here, reinforced by ice from Wales, it 
pressed against the Cotswold Hills, forming gravels and leaving 
Northern: Drift pebbles on their flanks, such as Millstone Grits and 
quartzite pebbles, but no flints. Such pebblesand gravels have been 
found, according to Lucy,’ at heights of 750 feet above the sea-level. 
If the ice reached such a thickness there must have been an overflow 
of water into the Thames Valley through the Andoversford Gap to the 
east of Cheltenham. Such thick ice would also pass over the Thames 
watershed into the Evenlode and Cherwell Valleys, and in this way 
Northern Drift found its way into the upper Thames Valley, where 
it is now found at heights considerably above the Tilehurst 
Terrace Gravels. As far as the British ice is concerned this would 
appear to have been the time of its greatest extension. However, 
the succession of events which preceded the advent of the Chalky 
Boulder-clay ice may have been much more complex than is here 
indicated. There is very little evidence of this in the area we are 
considering; but in Norfolk, Suffolk, and Northern Essex the 
complexity of the Drifts is very striking. 
Upon the westerly drifts of the Trent Basin there rest the Great 
Chalky Boulder-clay and its associated gravels and sands. It is clear 
from the arrangement of the deposits that, before the North Sea ice 
‘advanced up the Trent Valley, the Irish Sea ice had retreated a 
considerable distance. Whether in the Trent Valley to the west of 
Burton-on-Trent the eastern ice coalesced with that coming from the 
west is uncertain. Lucystates that along the flanks of the Cotswolds, 
and running up to the Marlstone Terrace to heights of about 610 feet, 
there is a line of gravel containing an abundance of chalk flints. 
Therefore, although the British ice may have been reinforced at this 
time by the ice which formed the Chalky Boulder-clay, its gravels 
only reach heights of 610 feet, whereas the earlier British ice formed 
gravels at heights of 750 feet. 
That the Chalky Boulder-clay glacier reached the upper.end of the 
Evenlode Valley is clear; for Lucy states that at Paxford, 34 miles 
north-west of Moreton-in-the-Marsh, he saw in a field which was 
being drained fully five feet of boulder-clay, containing some flints, 
quartzose pebbles, Lias, greenstone, Millstone Grit, and syenite from 
Charnwood. At Little Wolford, about 8 miles east of Moreton-in-the- 
Marsh, in a gravel-pit, were found pebbles of a hard red species of 
chalk which occurs not infrequently in the Wolds of Yorkshire and 
1 The gravels of the Severn, Avon, and Eyenlode, and their extension on the 
Cotswold Hills. 
