ON THE MEDICAL TOPOGRAPHY OF SINGAPORE. 467 
somewhat resembles the Isle of Wight and in size does not differ much. 
Its length is 25 g- miles, and breadth 14 miles, while it contains 
about 200,000 square acres, of which from 40 to 50,000 are under 
cultivation ; the rest, perhaps 156,000, is still in a state of primitive 
jungle, formed of high trees, and dense impenetrable under brush¬ 
wood (J. T. Thomson). The highest point of the island is about 
the centre, though nearer the south than the north, and the west 
than the east. This elevation is about 500 feet high, composed of 
granite, while its name, Bukit Tima , denotes the existence of an im¬ 
portant metal Tin, which was once obtained from it. The rest of 
the island is composed of ridges and sloping vallies. The ridges 
running somewhat parallel to the length of the island, which is east 
and west. The vallies arc of limited extent except one or two, in 
one of which Singapore town is situated, and which must contain 
20,000 square acres under cultivation, or cleared of jungle. The is¬ 
land is nearly surrounded by coral formation, but except at a few 
isolated spats as at Tdnjong Pdgdr, Pdssfr Pdnjdng, and in the Old 
Straits, the coral is not exposed at low water, and even these spots 
are but of a limited extent. Sand and mud, and here and there 
rocks of Sarid-stone and Iron-clay-stone is the general nature of the 
anchoring ground close in shore, as in Singapore Harbour. The 
rivers are not large but very numerous, so that whatever rain falls, is 
goon carried to the sea. Many indentations are seen in coasting the 
island, which might be mistaken for the mouths of large rivers, but 
they are merely creeks, or amis of the sea, with perhaps a rivulet 
opening into the inland aspect. Extensive marshes for the size of the 
island exist, but they are all with a few exceptions open to the sea 
and subjected to tidal influence. The only plutonic rock in the is¬ 
land is granite and its modifications; to it and Sand-stone, do we owe 
the mineral part of our soil, the rest is derived from animals and ve¬ 
getables. The upper soil of the island throughout, is of a light des¬ 
cription, principally sandy on the tops of the hills, and red soil at 
their base; or light red soil as the covering with clay as the base. 
Some lulls contain a little more alumina and Iron in their surface 
soil forming laterite, which on the hills varies in depth from 2 to 50 
