38 CONTRIBUTIONS TO THE ORNITHOLOGY OF INDIA. 



The less precipitous south-western coast is accompanied by a few 

 rocky cliffs, while the north-eastern coast is highly precipitous all 

 along the shore. The highest hills are situated in the northern 

 part of the island, apparently rising to an elevation of about 500 

 feet. Serpentine and gabbro form no doubt the great mass of the 

 island. 



" In the small bay on the south-western coast, Novara Bay, in 

 which the frigate was lying at anchor for a few hours, the irregular 

 and cliff-like shores are composed of common serpentine, often 

 traversed with veins of hornstone, and the same is the case with 

 the thickly wooded mountain slopes, as far as could be observed 

 in the small rocky beds of streams. The shore exhibited a very 

 great variety in the color of the serpentine, jasper and hornstone 

 pebble; besides these, however, there were noticed numerous 

 pebbles of a dark green diallage rock, which must no doubt be in situ 

 somewhere on the same coast at no great distance. 



" From the angular fragments of serpentine and other masses in 

 the course of decomposition, a ferruginous breccia is formed at the 

 foot of the hills, Avhile in the breakers the serpentine gravels are being 

 cemented by coral and shelly sand forming solid sandstone and 

 conglomerate banks which recall the Verde-antique, (Ophicalcite). 

 The plateau of the coast reefs extends 200 to 300 feet from the 

 precipitous shore into the sea. The whole of the island was cover- 

 ed with thick primeval forest which thrives well, even on the ser- 

 pentine ground. 



" In passing along there were observed, on the southern part of 

 the island and on the eastern coast, thin bedded rocks with a high 

 dip ; these were in massive cliffs almost perpendicular in the south- 

 eastern bay with a columnar structure ; their true nature remain- 

 ed, however, unknown to me, for I was unfortunately obliged to 

 use the telescope in place of the geological hammer. 



" Camoeta, Tbinkut, Nancowey with KatchalI/ form the middle 

 group of the Nicobar Islands. Trinkut is situated in front of the 

 eastern entrance of a channel between Camorta and .Nancowry ; 

 it is a low island surrounded by coral reefs, and on its southern 

 coast whitish-yellow argillaceous marls crop out. Camorta and 

 Nancowry exhibit a greater variety of formation, gabbro and ser- 

 pentine ; breccia and tufa ; clay marl with sandy beds ; coral rocks. 

 The channel between the two islands, Nancowry harbour, has 

 numerous small bays and corresponds with a transverse cleft, while 

 the Trinkut channel is a longitudinal cleft. The precipitous shores 

 of the former offer, therefore, the most instructive geological section. 



" The narrow western entrance to the Nancowry channel is mark- 

 ed by two projecting rocks, which have been washed out by the 

 force of the waves, making thus a natural gateway of rocks. Both 

 cliffs rising almost perpendicularly to about 80 feet, are formed of 

 a coarse breccia, composed of angular fragments of serpentine and 

 gubbro firmly cemented. I could not observe any stratification in 



