THE ISLANDS OF THE BAY OF BENGAL. 39 



this rock on the Camorta side ; it is here in cliffs with large 

 quadrangular blocks. On the Nancowry side, however, coarser 

 bands alternate with finer tufa-like ones, with a strike from S. S. E. 

 to N. N. W., and dipping about 85 degrees towards the west. 

 On the Camorta side, there crop out at two places below heaps 

 or masses of rocks, which Sink very properly regarded as friction- 

 breccias, cliffs of a more or less serpentine or gabbro-like massive rock. 

 " Among the pebbles on the strand, I also met with numerous 

 fragments of a reddish-brown rock, traversed by white calcite 

 veins, the rock which Kink called eurite. 



" These phenomena, at the western entrance to JNancowry 

 harbour, are thus perfectly identical with those which Eink has 

 observed at the entrance of the Ulala Bay, situated only a few 

 miles to the north. Further to the north the mostly bare hills 

 on the west coast of Camorta, recalling by their external shape 

 conical volcanic forms, attain a height of from 400 to 500 feet ; 

 they no doubt indicate the further extension of the serpentine 

 and gabbro rocks, which on Camorta and Nancowry are traversed 

 from S. S. E. to N. K W. by a longitudinal cleft. 



" In the interior of Nancowry harbour, wherever the rocks are 

 exposed on the projecting angles, they appear to be well-bedded, 

 whitish-yellow, clayey marls, alternating with banks of a fine- 

 grained sandstone, with serpentine and gabbro tufas. 



" Most instructive in this respect is the precipitous south- 

 eastern corner of Camorta, at which the coast line bends into 

 the Trinkut channel. The argillaceous marl formation is here 

 well exposed in cliffs of from 30 to 80 feet high. On the southern 

 side of the corner the transverse section of the strata can be 

 observed, dipping at 25° to 30° towards the west, while on the 

 eastern side, parallel to the longitudinal break, the beds crop out 

 horizontally one above the other. The argillaceous marl does not 

 contain fossils, is of a yellowish white color, and on the per- 

 pendicular walls it was covered with inch-long, white, very thin, 

 crystals of a silky lustre. The examination of these showed them 

 to be sulphate of magnesia. The clay itself contains, according to 

 Eink's analysis, besides silicate of alumina, iron-oxide and magnesia. 

 " The whitish-yellow clay marls of Camorta and Nancowry being 

 entirely free from lime have become famous since Professor Ehren- 

 berg (Berl. Akad. Monatsberichte, 1850, p. 476), by an examina- 

 tion of the samples brought by Dr. Eink, has shown that they are 

 true J?olt/cisti?ia-ma,r\s, like those of the Barbadoes. Ehrenberg 

 discovered in 1848 about 300 species, which were by Professor 

 Eorbes believed to belong to miocene (tertiary) deposits. Ehren- 

 berg says : — ' Especially well developed is this material on 

 Camorta, where, near Erederick's haven, a hill 300 feet high is 

 covered all over with variegated Poli/cistina-cl&y, while the Mong- 

 kata hills, on the eastern side of the island, are, according to Eink, 

 entirely composed of a whitish-clay resembling meerschaum • this 



