Cll. IX.] VEINS IN PRIMARY ROCKS. 175 



The distance of the Little Bounds lode, from the cliff to the 

 gap at the extreme point of Cape Cornwall, exceeds a quarter 

 of a mile ; and along this course the vein is well displayed in 

 several places, running in an undulating manner ; the part 

 next the Cape points more towards the north, while the 

 middle approaches nearer to the west; but the original 

 direction appears to be recovered at Little Bounds, so that a 

 line drawn through the two extremities, would bear about 

 N. W. and S. E., the usual direction of the lodes in St. Just. 

 It is evident by the diagram, that a considerable portion 

 of the lode is left on the southern side of such a line ; and it 

 is very probable that, if the lode could be traced farther in 

 its northern course, it would be found to pass as much on the 

 northern side of this line, just as the lesser curves of the 

 same lode may be seen to fluctuate between the opposite points 

 of the compass. 



Let us now turn our attention from this general view to a 

 close inspection, in order to ascertain the composition of the 

 vein, and the nature of its connection with the rocks which it 

 traverses ; and for this purpose three points will be selected, 

 denoted by the letters A, B, c, in the general plan. 



The part of the vein marked c, occurs on the shore imme- 

 diately below Little Bounds mine, and is situated between the 

 granite and the slate. In the cliff, a perpendicular section of 

 the same is exhibited, but the rock on either side is much 

 altered by decomposition and disintegration ; on the shore, 

 indeed, it has not perfectly escaped from the action of the 

 elements, but is so slightly changed, that its nature is very 

 apparent ; in both places, but particularly in the former, the 

 vein is regularly bounded by open lines or crevices, and 

 parallel thereto, both the vein and rock differ in structure 

 from the mass of these substances, having what is commonly 

 called walls ; at some points, however, in the spot c, the vein 

 and the adjoining rocks are intimately united, penetrating 

 into each other, and participating in the same mineral com- 



