R. Ml. Deeley—Boulder Clay in Derby. 295 
resembles many of the morainic deposits of the Lake District and 
North Wales. Although the matrix is chiefly finely broken up 
Keuper Marl and Coal-measure rock, there are occasional beds of 
what appears to be torrential sand and gravel much disturbed by 
subsequent ice action. Large boulders of Upper Carboniferous rocks, 
together with quartzite pebbles, probably derived from the Bunter 
Pebble Beds, are abundant, but Carboniferous Limestone is rather 
scarce. Flints are numerous and sometimes of large size. They 
are scattered throughout the whole depth of the deposit, not merely 
intruded into the surface portions. 
I have elsewhere pointed out! that in the Midlands flints are 
absent from the thick deposits of Older Pleistocene Boulder Clay 
and sand, but appear in great abundance in the clays and sands 
of Middle Pleistocene age. Associated with the Older Pleistocene 
Boulder Clays there occurs a thick deposit of sand, the Quartzose 
Sand, the false bedding of which indicates powerful currents from the 
north-west and south-west. The absence of flint from these deposits 
has a peculiarly interesting bearing upon the question of where the 
flints in the clays and sands of Wales, Cheshire, and Lancashire 
came from, and also when they were carried to the positions they 
now occupy: In Older Pleistocene times, when, as we have seen, 
the currents were favourable for the transport of flints from Ireland, 
flints were certainly not brought in any quantity into the Trent 
Valley. At least I have only found them in deposits of this age 
near the surface, into which they have no doubt been subsequently 
introduced. In Middle Pleistocene times, when the ice-flow was 
from the East or N.N.E., great quantities of flint and chalk were 
carried into the Trent Valley; for flints form a considerable pro- 
portion of the Chalky Sand even in the extreme north-westerly 
portion of the area; indeed they may be found in the Chalky Sand 
where it passes through the Biddulph Pass into the Cheshire Plain ; 
but the nearer we approach the hypothetical Irish source, the more 
scarce they become. I do not mean to assert that no flints have 
crossed over from Ireland; but the weight of evidence points strongly 
to the conclusion that the vast majority of the flints in the Boulder 
Clays and sands of North and South Wales came from the east of 
England during the Middle Pleistocene epoch. 
The presence of flint in the Burton Road and Littleover Boulder 
Clay, therefore, favours the assumption that the deposit is either of 
Middle or Newer Pleistocene age. Fortunately a deep excavation 
in the road, after passing through the red morainic clay, entered a 
couple of feet of blue silty clay full of rounded grains and pebbles 
of chalk. This deposit, which was clearly typical Chalky Boulder 
Clay, rested directly upon Keuper Marl, and was separated by a 
sharp line from the red clay above. Another shaft close by passed 
through clean-bedded Middle Pleistocene sand. Both the litho- 
logical and stratigraphical evidence, therefore, points to the con- 
clusion that the upper clay is the Later Pennine Boulder Clay.’ 
1 Q. J. G.§. Nov. 1886. 
2 That Mr. A. J. Jukes-Browne has misunderstood my argument concerning the 
DECADE III.—VOL. VI.—NO. Y. 15 
