164 LAEV^ OF INSECTS — SINGULAR FORMATIONS. 



of rocks projecting from the mud-plain wliicli sm-rounds the island. 

 In wading to the shore, we struggled through a deep, soft, dark- 

 coloured mass of what at first appeared to be ooze and slimy mud, 

 but which, upon examination, proved to consist almost solely of 

 the larvae of insects lying upon the bottom, producing, when dis- 

 tm'bed, a most offensive and nauseous odour. The mass was more 

 than a foot in thickness and extended several yards from the shore. 

 A belt of soft, black mud, more than knee-deep, lay between the 

 water and the hard, rocky beach, and seemed to be impregnated 

 with all the villanous smells which nature's laboratory was capa- 

 ble of producing. 



The point where we had effected our landing was found to be 

 a protrusion of an isolated pile of metamorphic rock above the 

 vast mud-plain, which latter extended to the northward and east- 

 ward, without a shrub or a bush or a blade of grass to be seen 

 upon its surface. This protrusion consisted of various kinds of 

 rock, pushed up from beneath, with a dip to the west from nearly 

 perpendicular to 45°. Slate, almost vertical, was found lying side 

 by side with a dark rock filled with pebbles and stones as large as a 

 man's head, consisting of what appeared to me to be granite altered 

 and burned by intense heat. This dark rock presented some indis- 

 tinct traces of a laminated structure, and may be slate very much 

 fused. Large boulders of granite and feldspar or quartz, with 

 scales of mica, lay strewn about, and I observed one with several 

 well-defined cubes of iron pyrites imbedded in it. The slate 

 seemed to be completely filled with pebbles and small broken frag- 

 ments of granite rock, with here and there a cube of u'on pyrites. 

 Boulders of feldspathic rock, seamed with white quartz, and con- 

 taining thin veins of jasper of a brick-red colom*, are occasionally 

 found in the slate. Near the western extremity of the point is a 

 different kind of rock — the direction nearly perpendicular. It is 

 of a more sandy structure, but is filled with the same pebbles. 

 The whole has been in a state of fusion. 



The mud-flat, where above the level of the water, is thickly 

 covered with round, dark-coloured, circular cakes, precisely resem- 

 bling, in form, colour, and appearance, the excrement of cattle 

 dried in the sun. Underneath the dry sui-face of these cakes is a 

 soft, black, and sometimes greenish mud, which, when the cake is 

 moved by the foot, and the dry covering pushed aside, emits a 

 most fetid, sulphurous odour, poisoning all the surrounding air. 

 The substance of which these lumps are formed appears to have 



