40 CONTRIBUTIONS TO THE ORNITHOLOGY OF INDIA. 



is, according to my analysis, a nearly pure agglomerate of beauti- 

 ful Eolycistina and their fragments, beside numerous Spongiolites.' 

 The species of Polycistina on the Nicobars are, according to Ehren- 

 berg, the same which compose the similar marl on the Barbadoes, 

 situated in nearly the same latitude ; but there are also some new 

 forms. 



"Near the level of the sea the clay marls, which locally contain 

 angular fragments of serpentine and gabbro, alternate with more 

 solid strata of psephitic rock, which is composed of strongly- 

 cemented angular fragments of serpentine and gabbro, and can 

 therefore be best designated as gabbro-tufa. It is remarkable that 

 this rock again includes larger and smaller pieces of the clay marl. 

 On the eastern coast, near the village Inaka (Enaca), a reddish 

 micaceous sandstone appears between the clay marls. 



" Similar are the geological conditions on the northern coast of 

 Nancowry. Between the villages Inuang and Malacca, the 

 whitish-yellow clay marls crop out in slightly inclined strata ; 

 between Malacca and Injaong, however, lies a precipitous cliff, on 

 which these strata rise almost perpendicularly, and are gradually 

 replaced by an accumulation of fragments of serpentine and gabbro. 

 At the projecting corner itself, the traveller faces a precipitous 

 cliff of about 60 feet in height, but being cracked and decomposed, 

 the true nature of the rock is recognised with difficulty. On a 

 fresh fracture, however, one soon observes a massive dialiage rock, 

 the laminar dialiage being clearly traceable in the nearly solid mass 

 of felspar. Narrow veins of quartz pass through the rock. 



" Erom here up to the village Injaong the strand is agaiu flatter, 

 and nowhere nearer than on the other side of the village, high, dark- 

 colored, rocks are a second time visible, indicating a massive rock. 

 These are the two places which Rink also has marked on his maps 

 as plutonic rocks. 



" Treis and Track. — On the north-western point of the small 

 island of Treis, highly upheaved banks of a fine-grained argil- 

 laceous sandstone of a greenish-grey color form a low precipi- 

 tous shore. The same stratified rock alternates with thin-bedded 

 sandy slates on the south-eastern coast of the small island 

 Track. Besides a fault, the strata form a saddle and strike from 

 S. S. E. to N. N. W. In a sandstone bank I found here im- 

 bedded a rolled fragment of a bituminous coal, the same of which 

 I met with a larger but equally rolled fragment on the strand of 

 the island of Treis. Of coal seams there was, however, no trace to 

 be detected; what might be mistaken for them from a distance 

 was only the shadow of softer sandstone banks, deeply weathered 

 out, or the darker color of some strata. 



" Pulo Milu, a small island on the no'rthern coast of Little 

 Nicobar, which Dr. Rink has so excellently described in all its 

 peculiarities, consists, in the higher parts, of a grey, fine-grained, 

 micaceous and calcareous sandstone in massive banks. Very often 



