Florence J. Relf—Some Wealden Sands. 299 
a mortar, and sifted through muslin. This method has been adopted 
at Bedford College, because it is difficult to ensure that no foreign 
grains are clinging to an ordinary sieve. The fine material was 
washed to remove the mud, treated with acid, and finally separated 
in KI Hele. As a result it was found that nearly all the heavy 
particles consisted of brown tourmaline, generally irregular in shape, 
but cceasionally prismatic. Zircon crystals were comparatively rare. 
Some corundum was found. The rarity of free zircon would, of 
course, be explained by the fact that it commonly occurs included in 
quartz and biotite, which in this case was not broken up. 
On the whole, the result of this examination confirms the idea that 
the sands were mainly derived from a granitic rock. It remains to 
seek a large area occupied by suitable rocks, and exposed to 
denudation in the early part of the Wealden period. 
During Jurassic times there was probably a large land area to the 
west and south-west of the present position of Great Britain. This 
land included the western mountainous districts of Wales, the 
Cornwall and Devon Peninsula, and the north-western peninsula of 
France; but these portions of modern Europe represent the eastern 
seaboard only of the supposed continent, which is thought to have 
extended into Ireland, and far to the south-west and north. It is the 
area referred to by Professor Bonney,} in an article on ‘‘ Pebbles in 
the Trias ’’, as ‘‘the ancient mass of Archean crystallines, which once 
swept round the Scoto-Scandinavian region to north-western France’’. 
In the Portland epoch the borders of this land extended eastward 
into Dorsetshire, and in the succeeding Purbeck and Wealden periods, 
continued upheaval had still further increased the land area. 
When the Ashdown Sands were being deposited, the greater part 
of England must, therefore, have been land covered by Jurassic 
deposits, that 1s, mainly by dark shales and limestones—not the kind 
of material from which a quartz sand could be derived. The only 
parts not covered by Jurassic rocks were the areas which had formed 
part of the western continent, with, perhaps, a fringe of Triassic 
rocks; and the extreme east of England, north-east of the London 
Basin. As far as can be judged by borings in this eastern district (at 
Harwich and Ware, for example), this land area seems to have been 
formed, at that time, by rocks of Silurian and Devonian formations, 
which were composed of beds of shale, with thin beds of limestone 
in the Silurian and of grey and red sandstone or quartzite in the 
Devonian. 
It seems, therefore, fair to conclude that the source of supply of 
the sands under consideration must be sought among the rocks of the 
western continent. In the remains of it which have survived to the 
present time are masses of granitic rock, and from such rocks there 
is, as we have seen, no difficulty, mineralogically, in deriving the 
Wealden Sands. 
The general angularity of the fragments makes it probable that the 
material was brought directly from the granitic rock to its present 
1 Professor Bonney, ‘‘ Pebbles in the Trias’’: GOL. MaG., Dec. IV, 
Vol. II, 1895. 
