164 Mr Rastall, The Minerals of some Sands : 
The final residue was nevertheless large in amount and contained — 
a considerable variety of minerals. Black grains of magnetite are 
very abundant, and the chief transparent minerals found are 
zircon, rutile, garnet, tourmaline, staurolite, hornblende, augite — 
and probably spiel. Zircons are very common and rather large: 
sometimes idiomorphic, but more commonly well rounded; un-_ 
usually so for such a hard mineral. Rutile is also very plentiful — 
in prismatic crystals and in grains varying in colour from yellow — 
to deep red. It is possible that some of the deep red grains here — 
assigned to rutile may really be cassiterite: this would be difficult 
to prove. Pale pink and brown garnets are common in well 
rounded grains rather larger than the average size. ‘There are 
also a few opaque white, yellow and brown grains of indetermin-— 
able nature, and a very little opaque red iron oxide, probably 
haematite. Kyanite is very rare. When examined on a dark 
background the most striking feature of the sample is the | 
abundance of magnetite and rutile, and its general appearance is 
very characteristic. 
(2) Dane Hill, Kennett. 
At this locality, which is about four miles north-east of New- 
market, there are curious patches of marl or loam resting on 
gravel. The marl is very pale grey in colour, weathering pale | 
yellowish brown. It is very fine in texture and soft, disintegrating | 
readily when placed in water. By repeated washings much fine 
mud can be removed, leaving a residue of pale brownish sand, 
with small chips of flint and some white mica. It is difficult to 
get rid of the last residue of the mud by washing, and this is 
important, since separation of heavy minerals is prevented by the 
presence of mud. However addition of a little acid facilitates the 
process, and produces a copious effervescence, thus justifying the 
designation of marl employed above. Larger elements which fail 
to pass the first sieve are small in amount, consisting of pinkish 
quartz and grains of iron oxide, together with chips of pale blue © 
flint. 
The portion sinking in bromoform also for the most part 
consists of iron oxide in rounded and curiously polished grains. © 
After further treatment with acid these are removed, and all that | 
remains is a very few rounded grains of garnet, together with still 
fewer crystals of hornblende, zircon and rutile. These grains are 
not by any means exceptionally small: in fact they are consider- 
ably larger than in the sands from Newmarket station and from 
the cemetery pit at Exning. This fact probably has some bearing 
on the origin of the marls, as will be explained more fully in ue 
case of the Exning deposits. 
