1837.] 



Bombay Islands* 



161 



apparent until they are transversely fractured. The rock has a purplish 

 aspect, and is evidently decaying in many situations, by the readiness 

 with which the atmospherical influences act by the medium of the 

 amygdaloidal cavities. Before the blowpipe per se this rock simulates 

 fused basalt. 



4. Yellowish gray claystone porphyry, at the lower cave of Elephan- 

 ta. The predominating particles have a yellow resinous appearance? 

 with a black basis. 



5. Green claystone porphyry, appearing at Baboola Tank ; fine- 

 grained, and admitting of a good polish, interspersed with dark-coloured 

 soft particles, which have an even fracture, and appear to be small 

 masses of indurated clay. 



6. Amygdaloid, with a light coloured porphyritic basis and green 

 cavities, accompanied generally with large crystals of calcarious spar, 

 from the neighbourhood of Parell. The calcarious spar is sometimes 

 dark-coloured, probably from the effect of reflected light upon it in its 

 impacted situation. 



7. Numerous large fragments of shell conglomerates may be observed 

 on the shore of Elephanta, consisting of a nucleus of porphyry, or 

 amygdaloid, closely surrounded by adhering bivalves, which afford 

 means of extending the limits of the growth of the mangrove. 



The amygdaloidal cavities contain numerous species of various classes 

 of minerals, but those which are of very common occurrence are in- 

 cluded under these genei;a. 



, CLASS 1.— -ACIDS. GENUS, SILICA. 



1 . Rock crystal — termed Palunca in the Malabar language, Spadika, 

 in the Grantham dialect — occurs very abundantly in each of the islands, 

 in the form of crystals, varying from the most minute size to half an 

 inch in length. 



2. Common quartz. 



3. Milk and Rose quartz. 



4. Chalcedony. 



5. Amethyst. 



6. Agate. 



7. Cornelian, rare in the immediate neighbourhood of Bombay. 



8. Oriental jasper, or blood-stone, also rare, but abundant in Guzurat 

 and Cambay. 



CLASS II. — ALKALIES. 



I. GENUS LIME. 



Calcarious spar. 



II. GENUS ALUMINA. 



1. Mesolite, whose composition is expressed by the formula 3 Al. 

 S + (4 C + i ft") S 3 + 31 Aq* 



* The result of an analysis by me , Jameson's Journal, I8?>i , 



