53 
Flora of Narcondam and Barren Island. 
of tlie northern half, shows a second snhconcentric ridge separated from 
the true rim by a gorge that debouches on the east side of the island. 
Gorge and ridge owe their origin, however,—like the ridge and ravine of 
the same nature, but of more imposing proportions, that occur at the 
south end of Narcondam—to subaerial denudation, not to volcanic action. 
The excentric position of the newer cone, with the lesser relative 
height, and the steeper seaward slope of the northern half of the origi¬ 
nal ci’ater, seems to point to subsidence of that half. Perhaps 
the explosive eruption which elfected the breach to the west may have 
had some connection, direct or indirect, with this subsidence. The vol¬ 
cano represented by the outer cone was doubtless at one time much 
higher than it is now. 
At the landing-place in the breach there is a hot spring on the 
beach ; the temperature of this spring is steadily falling, and at the 
time of the writer’s visit was 106° ¥* The spring doubtless only 
represents percolation of rain water through the heated newer mate¬ 
rials—the inner cone and lava streams—contained within the circuit 
of the ancient crater.f 
The anchorage in the bay at the breach is of the most uncom¬ 
fortable description ; the safest anchorage is opposite a small bay with 
a sandy beach, a Fandanus sea-fence and a line of Coco-nut trees, on the 
south-west side of the island. Landing by boat is, however, usually 
quite easy on the beach at the hot spring to the north of the point where 
the lava stream falls into the sea; the surf that rolls into Anchorage 
Bay must make it impossible, as a rule, to land there. 
At Landing Bay the boulders and stones on the beach, bathed by 
the water of the hot-spring, are covered by a species of Calothrix which 
occurs in considerable quantities. Another, Alga, also a Calothrix, was 
obtained from bare rocks in one of the gorges ; no marine Algoe were seen. 
On the beach itself, behind a small bed of drift, are some examples of 
Ipomoea hiloha ; the drift contained, in addition to fruits and seeds of 
species noticed in the island, fruits of Barringtonia speciosa and of 
Heritiera littoralis.% Close to the beach and to the lava flow is an ex¬ 
ample of Pongamia glahra ; a little further inland to the north of the 
lava is a considerable grove of Flueggia microcarpa, with quantities of 
Mitreola oldenlandioides, in the sandy soil beneath. Beyond this grove is 
* Prain : Proceedings As. Soo., Bengal, 1891, p. 84. 
t Mallet : Memoirs of the G-eol. Survey of India, xxi, 274. 
$ Barringtonia s'peciosa occurs in Narcondam, and it may possibly also occur at 
some of the hays on the south-west and south of Barren Island, where the surf 
made landing impracticable. But Heritiera littoralis, the fruits of which were col¬ 
lected in Narcondam also, does not seem to occur in either island. 
267 
