330 Dr. R. D. Thomson on the [May 



printing on paper; and being body colours, which conceal 

 what is beneath them, they are used for black and various 

 other coloured grounds. A brilliant effect is thus produced 

 at small expense. 



Article II. 



Sketch of the Geology of the Bombay Islands. By 



Robert D. Thomson, M. D. 



( Continued from p. 304. ) 



ELEPHANTA ISLAND. 



The form which this island presents at a distance is some- 

 what pyramidal, but on a nearer approach it is found to 

 consist of two distinct hills, with an intervening valley. 

 This vale is profusely studded with trees and bushes, as 

 well as the hills, which are clothed with wood from the 

 water's edge to the summits. Many of the trees are tall 

 and stately, as the brab or palmyra, while others are covered 

 with the densest foliage, as the tamarind, with its rich 

 green leaves and elegant blossoms. In the dry season the 

 island exhibits the best appearance from the summits of the 

 hills, or by approaching it from the sea, for at that time the 

 earth is dry, parched, and as if baked, being crossed in every 

 direction with fissures, which greedily suck up tbe rain 

 whenever it happens to fall, and, of course, is destitute of 

 that rich vegetable carpet which covers it during the pre- 

 valence of the monsoon. Then the soil is one mass of 

 verdure ; not a spot is naked ; the paddy ground being 

 enlivened with the presence of the rice crop, and the forest 

 waste adorned with grasses and elegant flowers. The rice 

 ground is very limited, and is situated at the lower part of 

 the vale, in the immediate vicinity of the village of Galli- 

 pooti. It is divided into parterres, or small inclosures, 

 fenced with impervious hedges of pricklypear (Euphorbia 

 neriifolia and terucalli.) The whole island is one mass of 

 rock, and the thin scattering of soil which hides but scan- 

 tily the main constituent of the island, is merely derived 

 from the disintegration of the latter. At the southern 

 landing place there is a ledge of large masses of amygdaloid, 

 (of which the cavities have been washed empty, if we except 



