OF THE TENASSER1M PROVINCES. 
3S9 
Passing to the coast, its appearance seaward is that of a 
plain of a varying breadth, backed by a series of mountain 
ranges ; those nearer the coast having an altitude of 500 to 
1,500 feet, and those which form the main range, approaching 
the height of 4,500 to 5,000 feet. These ranges have a uni¬ 
formly undul: ting outline, and otherwise possess the same 
character as those in the Straits of Malacca, being cover¬ 
ed to their summits with a dense forest vegetation : Ap¬ 
proaching the northern boundary on the Salween river, their 
features become more varied, from the rugged and conical 
shape of the limestone hills (blue mountain limestone) which, 
without any general line of direction, rise abruptly from the 
alluvial plains to a height of 1,500 to 2,000 feet and are seen 
distributed throughout the landscape in isolated ranges. The 
same cavernous limestone is found accompanying the sand¬ 
stone hills in detached masses, throughout the whole extent 
of coast. From this point the main range of hills, forming the 
boundary between these Provinces and Siam, is distinctly 
traceable in the clear atmosphere of the N. E. monsoon, 
at a distance of 65 miles, shewing a bolder outline than those 
intermediate with some of the peaks at a height of 5 to 6,000 
Little information that can be relied upon has hitherto 
been obtained on the geological conformation of the main 
range of mountains, or of the elevated vallies traversed by 
the Thoungyeen, Hloing, Bwai, Dagyue and Houndran rivers 
—the principal feeders of the lower part of the Sal win* ; 
from each other prior to the peroxidation. The iron disguises the rock and 
deceive! observers. Much of the laterite of the Malay peninsula, and we be¬ 
lieve much of that of the Indian also, does not originate from the decomposition 
of plutonic or volcanic rocks, but is simply the ordinary sedimentary rock dis¬ 
guised by the peroxidation of the iron which rose into it from the subterranean 
plutonic intumescence in which the Peninsular elevations originated. The 
evidence on which this opinion is based is very extensive and conclusive. (Journ, 
As. Soc, of Bengal for 1847 p. p 520, 21 j 670, 71, 79 to 81 ; Arch. Vol. XI 
p. 96-103, 625-631 ; Notices of the Geology of the Straits of Singapore, GeoU 
Soc.) Ed. 
* Captain Latter, the superintendent of forests, in his report on the teak 
localities of these Provinces lately published, thus notices the valley of the 
Thoungyeen. . , . t . , , , 
“The region occupied by the Thoungyscn forests consists of an elevated 
valley, (about 800 feet higher than the Maulmain plains) having the Donaw 
range on the west, and the range called the “Toungnyo,” on the east. These 
two ranges, slightly trending towards one another, meet, and form a sort or 
“ cul de sac,” at. the bottom of which rises, and through the whole length of 
which, in a north westerly direction, flows the Thoungyeen river. It runs parallel 
to the Donaw range, which sinks gradually into the plains to admit of its junc¬ 
tion with the Salween river. The Toungnyo range, as far as I could learn, 
runs due north, proceeding into regions unreached by our geography. I should 
