the Island of Tristan da Ciinha, ^c. 485 



The mountain appears to have been rent asunder by some vio- 

 lent convulsion, and the fissures filled up by a hard stony mass of 

 a blueish or a reddish colour, and of the nature of trap, forming 

 regular veins, the ramifications of which can be traced by the eye 

 to a great height in the face of the rock. The sides of these veins, 

 ■where they come in contact with the rock, are invariably in a 

 semivitrified state, and exhibit obscure marks of crystallization. 



Along the north-west side of the island there runs a belt of low 

 land about six miles long, varying from a quarter of a mile to a 

 mile in breadth, and presenting to the sea a perpendicular front 

 from fifty to three hundred feet in height. The whole of this 

 plain is a confused assemblage of stony fragments, scoria, and 

 other volcanic products, resting on a bed of lava. All these mat- 

 ters are in a progressive state of disintegration, and the greater 

 part of them reduced to mere nuclei imbedded in their consti- 

 tuent elements in the state of a black indurated earth. 



The northern extremity of the plain is in a great measure cleared 

 of its wood. By setting fire to (he grass the trees have been so far 

 scorched as to destroy their vegetation ; but they still lie strewed 

 along the ground, and it will cost some labour to remove them. 

 The rest is still in ii stale of natuic, covered with an impenetrable 

 copse. 



The surface of the plain, though apparently smooth and even 

 while clothed with its native herbage, is in fact extremely irreou- 

 lar, being every where broken by small ridges of loose stones 

 concealed under a mere scurf of soil. Between those ridses, how- 

 ever, the soil is pretty deep, and consists for the most part of the 

 remains of decayed vegetables, Avith here and there a substratum 

 of alluvial earth approaching to the nature of clay. It is soft, 

 spongy, retentive of moisture, and possesses most of the charac- 

 ters of peat. This soil has been found admirably adapted for the 



3 R 2 production 



