1835.] Geology of the Bombay Islands. 297 



communication may be kept up in such circumstances. The 

 prevailing rocks in this little insulated land are the same 

 as those already mentioned, with the occasional appearance 

 of basalt as if in dykes. At the southern point a dangerous 

 rocky mass extends out to sea nearly three miles in length, 

 assisting, with the aid of Tull Reef, in rendering the mouth 

 of the harbour extremely narrow, for, if we deduct these 

 obstructions to navigation, its span is not above four miles, 

 although the distance from Coulaba to the nearest point of 

 the continent equals seven miles. 



The Coulaba Reef has been termed, from its forked figure, 

 the Prongs, and appears to consist of the general rock, in 

 a highly indurated form. The same series occurs at the 

 New Bunder, by the Apollo Gate, where the amygdaloid 

 appears to lie over the porphyry, which is very hard when 

 first exposed, and is employed as a building material. The 

 New Bunder is formed of it; but notwithstanding the 

 excellent quality of the stone for enduring the effects of 

 aqueous friction, it is remarkable that an effectual plan has 

 not been fallen upon to render the building of the jutty 

 durable, as it is continually undergoing displacement from 

 the action of the tide. The utility of the Bunder cannot be 

 disputed for the numerous ships which annually increase in 

 frequenting this excellent port, and the situation of this 

 quay, from its being exterior to the fort, is very important, 

 and is perhaps safer than the Old Bunder during the height 

 of the monsoon. 



To the north of the town the surface begins to rise 

 gradually until the small eminence of Mazagon is formed. 

 Beyond it are Parell and Oblong Hills, all preserving a 

 rounded outline, thinly sprinkled with cocoa-nut trees, 

 (Cocos nucifera) and affording some pasture land. At Ba- 

 boola, a tank has been cut out of the solid rock, supplied 

 with a broad flight of steps, to enable the inhabitants to 

 have free access to the water, which they employ for all 

 purposes. It is from similar reservoirs that the principal 

 supplies of water for domestic purposes are obtained, and 

 for the use of the crews of ships visiting the harbour. 



As much discussion has taken place with regard to the 

 influence which water procured from such sources may have 

 upon the health of seamen, by affecting the alimentary 



