REMARKS ON CONCHOLOGY AND MALACHOLOGYi 233 
Ima and others. I am informed by Mr. Thomson, the Government 
Surveyor, that wherever he has had occasion to make excavations 
in the low ground of Singapore, similar appearances present them¬ 
selves, that in all the brick pits the clay is of the same description 
and also contains shells; moreover that in the Kallang valley, corals 
similar to existing species are to be found at the depth of six feet; 
add to this the fact that the growth of coral is yearly diminishing 
the depth of w r ater in the neighbourhood, a good example of which 
is seen at the entrance to New Harbour where there is a small peak¬ 
ed island, between which and Singapore, the coral has grown so ra¬ 
pidly that it is thought the island will in a very few years form a 
part of Singapore; taking therefore all these circumstances into 
consideration I conceive that the existence of shells in such si¬ 
tuations may be rationally accounted for on the supposition that 
most of the valley ground of Singapore was originally sea, and 
has been altered and adapted to the use of man, chiefly, if not solely 
through the agency of coral. 
Most of the shells in the annexed list may be found described 
in any work of reference on this subject. I shall therefore mere¬ 
ly notice individually a few whose exterior forms, or the pecu¬ 
liar habits of their inhabitants, are not, so far as I am aware, 
very generally known. 
The Magilus antiquus has lately been found north of Penang 
in the neighbourhood of Junk Ceylon, the natives set some value 
on them, and occasionally wear them as ornaments; the shell is sin¬ 
gular anti apt to be mistaken for a petrifaction, being dense in 
structure, diaphanous, and much like alabaster. It has been often 
figured and described by naturalists, but the animal inhabiting it 
is I believe unknown, unless described in some very recent pub¬ 
lication; it is supposed to be a Gasteropod, though this is rather 
doubtful, as the shell is said to be generally found imbedded in co¬ 
ral or madrepore: it is probable that this point might be satisfac¬ 
torily settled by a careful examination of the above locality. Among 
other interesting discoveries lately m ide on that part of the coast, 
is a layer or stratum ol grey limestone, of considerable extent, com¬ 
posed almost entirely ol petrified shells. I have been fortunate enough 
to obtain a specimen for examination which contains three distinct 
species, apparently fresh water shells; two of them I have never 
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