Florence J. Relf—Some Wealden Sands. 297 
a s.g¢. of 8°317. This separated the heavier minerals from the 
tourmaline. 
It was found advisable to use a fairly large quantity (10 to 20 grams) 
of sand to begin with, to ensure a greater degree of accuracy in 
subsequent calculations. In each case the proportion by weight of 
the heavy material was worked out and the size of the minerals noted. 
As a result of these investigations it was found that the sands are 
composed chiefly of quartz, but that there is a small proportion of 
heavy minerals, notably of tourmaline and zircon. Other minerals 
found include felspar, rutile, anatase, staurolite, kyanite, garnet, 
and fluor. : ‘ 
WEIGHT OF HEAVY MATERIAL IN 1 GRAM OF SAND. 
; Gram. 
Forest Row. A ‘ A 4 5 -003 > 
i 3 3 - -0015 
-0023 -Average -0014. 
- 0003 
-0003 
Battle. 
0015 
001 
Pee Average -0016. 
-003 | 
-0012 
Hridge. -0008 
Lindfield. -0052 
-009 } Average -0071. 
0025 \ 
-002 J 
-0008 
-0004 
Ardingley. - Average - 0022. 
Hquthen. 
Wissant. 
BSaQureUneOQsHowrrynaw 
RESULTS OF DOUBLE SEPARATION. 
Forest Row. C. . 
Of the material with s.g. above 3-131, 22 per cent had s.g. lower than 
3-317 (this was mainly tourmaline), and 78 per cent higher than 3-317 
(this was mainly zircon). 
MINERALS. 
Quartz.—The quartz grains vary in size from ‘03 mm. to ‘13 mm., 
the average being about ‘07 mm. They are usually angular, though 
occasionally they are sub-rounded. The grains generally contain 
inclusions which are not, as a rule, arranged in any definite lines. 
Felspar.—Orthoclase felspar is present in very small quantity only. 
As the result of an attempt to separate this mineral from the quartz 
by specific gravity, after the minerals heavier than quartz had been 
removed, it was found that the amount of felspar obtained from about 
10 grams of the material was barely sufficient to weigh, there being 
only enough material to mount under one small coverslip. The felspar 
fragments are, on the whole, much smaller than the quartz, and, as 
is usual with very small fragments, they are even less rounded. 
Zircon.—The zircon crystals in the sands show, as they commonly 
do, very good crystal shape, and they are seldom broken. The 
individual crystals vary, however, and four types have been noted :— 
