40 
Flora of Narcondam and Barren Island. 
a level one, for if slopes so gradually northwards that, as it passes into 
the Bay proper, its depth is still 1400 fathoms. No such clear delimita¬ 
tion exists between Sea and Bay ; the plain that forms their common 
floor still slopes gradually upwards towards the north till, in the neigh¬ 
bourhood of Lat. 20° N., the edge of the shelf of the Gangetic Delta is 
reached. 
The southern edge of the floor of the Sea of Bengal may, in spite 
of its depth of over 2000 fathoms, be taken as, in a sense, the margin 
also of the continent of Asia, for there is more than the rapid increase 
of slope towards the bottom of the Indian Ocean to characterise it. To 
the west it coincides with that remarkably abrupt terrestrial elevation 
which results in the island of Ceylon, off the south-west coast of which 
island, less than 40 miles from the Basses, the ocean depth of 2300 
fathoms is reached. To the east a precisely similar terrestrial eleva¬ 
tion, though of smaller size and much less height, is met with. Just as 
Ceylon lies, a pear-shaped eminence, to the east of Lon. 80° E., so to tho 
east of Lon. 90° E. lies the pear-shaped eminence known as Carpenter’s 
Ridge,* a terrestrial mass that rises from a depth of 2300 fathoms in 
Lat. 5° N., till in Lat. 6° N. and Lon. 90° 30’ E., it reaches a point 
which carries only 1380 fathoms. The ‘ thick end ’ of the pear in both 
cases faces the south, and just as the ‘ stalk,’ in the case of Ceylon, tails 
north-westward into the Indian Peninsula, the ‘ stalk,’ in the case of 
Carpenter’s Ridge, tails north-eastward into Middle Andaman. There 
are these differences between the two; the connecting ridge between 
Ceylon and India carries nowhere more than 8 fathoms, that between 
Carpenter’s Ridge and the Andamans carries 1600 fathoms, while the 
highest point of Carpenter’s Ridge is as much beneath as the highest 
point in Ceylon is above sea-level. 
The third area (c) is the land-locked seaf, bounded on the west by 
the Andamans and Nicobars, on the north by the Irrawady Delta, on 
the east by Tenasserim and Kedah, and prolonged south-eastward into 
the Straits of Malacca, between Sumatra and the Malay Peninsnla. 
This sea is not, as a rule, distinguished by any general name, though 
* Alcock: Annals and Magazine of Natural History, ser, vi., iv., 377. 
t Carpenter: Kecords of the Geological Survey of India, xx, 48, had proved, as 
conclusively as it is possible in the absence of actual soundings to prove, that this 
body of water must be separated from the Sea of Bengal by a ridge nowhere 
deeper than 760 fathoms, the shallowest sounding known between Acheen and the 
Nicobars, since the temperature at 1200 fathoms east of the ridge is that appropriate 
to 740 fathoms to the west of it. Since then the indication of 736 fathoms as the 
depth on the line from the Nicobars to the Andamans is a striking confirmation of 
the justice of Carpenter’s reasoning. 
254 
