m 
SKETCH OF THE PHYSICAL GEOGRAPHY 
In the vallies of Singapore pure white pipeclay, of which fine white 
porcelain ware has been made, is found abundantly. It appears in 
general to be derived from the decomposition of the subjacent pluto- 
nic rock. 
The vegetable deposits which occur in the alluvial tracts, and are 
frequently thick and extensive, are spongy masses of dead plants, (in 
which trees are often thickly imbedded), saturated and swollen with 
water, and resting on a black mud. When drained the level sinks 
considerably. 
Shells are found, often very abundantly, in the alluvial clay. Beds 
of coral are also occasionally met with. The infrequency of deep 
excavations is probably the reason why, in localities inhabited from 
very ancient times, human remains are so seldom brought to light. 
In the inner part of the Singapore plain a piece of coir rope was 
found 6 feet below the surface, and a piece of wood bored through 
and having the hole filled with the twisted fibres of a piece of rope, 
was found in the town of Singapore at a depth of forty feet.* In 
3. Since in the lower portion of the Elbe, the mud, consisting of a mass 
of clay and slime, which often interferes with the navigation, only accumu¬ 
lates so far up as the flood tide is perceptible, hut above this point, the bed 
of the river consists of pure siliceous and other sand, it is evident, that the 
cause of this singular phenomena, which has hitherto not been sufficiently 
explained, is principally owing to organic conditions. It appears, in fact, 
that the mixture of river and sea water gradually kills vast multitudes of 
the minute organic bodies, and causes them to fall to the bottom, and form 
these accumulations. 
4. The marsh land of the lower district of the Elbe, below Hamburg, 
and, probably , of all rivers (lowing into the ocean, and considered as hu¬ 
mus, does not merely or even chiefly consist of matter brought down by the 
stream from distant regions ; and still less is.it a local production of the 
minute animalcules existing in river water ; but it is to a very considerable 
extent derived from organic beings existing in the ocean. 
5. If we deduct the admixture of fine sand as a matter of uncertain ori¬ 
gin, we shall find, not only at Cuxhaven, near the mouth of the Elbe, but 
also at Gliickstadt, that from one quarter to one third of the mass of fresh 
mud is owing to the influence of marine animalcules, and that above Ham¬ 
burgh, as far as the flood tide extends, the proportion is about half as great $ 
but it has been already shown, that what appears to be fine sand may also, 
in a great measure, be an altered state of organic siliceous shells. — Q. Jour¬ 
nal Geological Society, vol. I. p. 252. 
* Mr. Thomson bored through 10 feet of blue mud and 30 feet of ferru¬ 
ginous earth before this piece of wood was brought up. Other 40 feet of 
hard ferruginous earths and clays were pierced at this locality (near the 
Hindu leraple.) 
At the Gaol 55 feet of blue mud mixed with shells were found resting on 
red earth mixed with the bark of trees. 
