132 SKETCH OF THE PHYSICAL (GEOGRAPHY 
the banks, which are there 15 feet high, and inundates the whole 
country to the sea, a breadth of 50 miles. 
The remarks of Mr. Anderson on the country of the Assahan river 
seem to show that the whole of it is alluvial, and the fact, before al¬ 
luded to, of his finding- near the hills a surface bed of red earth 8 feet 
thick, resting' on mud and sand, is a strong proof that the gradual 
elevation of the plain towards the interior is due to accumulatio n 
from above in the mode before mentioned, and not to upheaval from 
below. Mr. Anderson mentions that the Malays have a tradition 
that the sea was formerly at Pulo Gorab, which is 30 mile up the 
Belli river, and affirm that, 200 years ago, it was at Serantan, 15 
miles up the river Assahan. These traditions at least shew that the 
advance of the land is so marked as to force itself on the observa¬ 
tion of the natives. 
Upon a review of all the information we possess regarding the 
great eastern plain of Sumatra, the most reasonable conclusion at 
which we can arrive seems to be that it is entirely formed of alluvi¬ 
um, and that the western shore of the Straits was, at some ancient 
epoch, from GO to 100 miles more to the westward than it now is. 
If we extend our observations to the southward, we find that the 
<m;at flat alluvial plain extends across the basins of the Palembang 
and Tulang Bawang rivers to the Java sea. It is thus almost cer¬ 
tain that the greater part, as it is very evident that at least a large 
part, of the low country of Lam pong, Palembang, Jambi, Siak See., 
were once covered by the sea. The bearing of this circumstance on 
the modern geological history of that Archipelago of which Singapore 
is the most northern Island will be adverted to in a future paper. 
Of the numerous rivers which fall into the Straits of Singapore 
the largest is the river Johore, the estuary of which is the finest in 
the Peninsula. The river itself has a long course, and preserves a 
considerable breadth and depth until it bifurcates. A he eastern 
branch, called the Lingiu, rises in Gunong Lulunrat, the highest of 
the most southerly mountain range, and the western, the Sayong, 
amongst low hills. 
Although the eroding action of tides and currents is feeble com- 
