A- 105 -- 



The sample is very crumbly. These veins are sepa- 

 rated by another of hard conglomerate, about an inch 

 in thickness, which seems to contain a quantity of 

 iron. Indeed, the conglomerate is coloured red to 

 brown by the presence of this mineral. 



At the spot where it might be supposed the 

 centre of the crater had been, the flat surface of the 

 conglomerate . rock is strewn with basaltic boulders. 

 Small pieces of rock crystal, carbonate of lime, 

 abound in a variety of sizes up to about 2 or 3 inches 

 in length, and to an inch in thickness. 



The conglomerate rocks on the southern side 

 descend in a precipice to the sea, on the eastern and 

 western sides the descent is steep and precipitous ; 

 but on the northern side the descent, although at first 

 steep, slopes at last gradually to the central plateau 

 of the island ; and the conglomerate rock is, as far I 

 could make out, overlaid by the basaltic rocks. 



A dike of rock runs out, in a northerly direction, 

 from the moat northerly of the Deux Mamelles, 

 towards the Pigeon House Rock. This dike is of au 

 aqueous conglomerate rock, which has been altered 

 by heat. The composing rock is shattered to shivers, 

 which vary in size from that of road macadam 

 upwards. It is of varied degrees of hardness, 

 resembling soft and hard burnt bricks. A line drawn 

 between the furthest north of the Deus Mamelles to 

 the Pigeon House Rock would indicate the highest 

 part of the central plain of the Island, from which the 

 surface of the plain slopes to the east and west to the 

 sea. . The rock that underlies the central plain is 

 basalt. Loose boulders of the same rock, as well as 

 of coral, are scattered over its surface. 



How came these blocks of coral to be on this 

 plain at, comparatively speakipg, somQ distance from 



