372 



TRANSACTIONS OF THE 



eluded, therefore, that the former, which form a very 

 large majority of the whole, are oldest. 



It may be observed that the term heaved,'^^ is used 

 here as applicable only to a longitudinal shift of the vein, 

 and ''thrown up^^ or ''thrown down^^ to those shifts 

 which take place on the meeting of two veins underly- 

 ing in different directions, in their downward course. 



In describing the heaves as to the right or left, is 

 meant, that when lodes are heaved by other veins, they 

 may be found on the other side of the traversing veins, 

 by turning either to the right or left hand. The more 

 recent tin lodes comprize most of those which underlie 

 southwards. A particular description of tin lodes will 

 be found equally applicable to both these classes. 



In order to prove, on the principles already laid down, 

 that the tin lodes are the most ancient of the true veins, 

 it must be shown that they are traversed by true veins 

 of every other description. 



They are traversed by east and west copper lodes. 

 In one instance two tin lodes are traversed by one copper 

 lode, and both are heaved about 12 feet. In another, two 

 copper lodes traverse one tin lode, w^hich is heaved by 

 both of them. At the Huel Peever mine, a tin lode un- 

 derlying south, has been rfiet in its downward course by 

 a copper lode underlying north, and has been thrown up 

 8 fathoms. It is also traversed by two slides, both under- 

 lying north; by one of which it is thrown down 14 fathoms^ 

 and by the other thrown up 9 feet (pi. 25, fig. 2); and at 

 another point in the same, it has been heaved 70 fathoms 

 to the right by two cross courses : pi. 25, fig. 3. A singu- 

 lar heave of tin lodes, by a copper lode, was observed in 

 the Sealhoie mine. A part of a very rich tin lode was 

 heaved so exactly opposite to a part of an unproductive 

 lode, as to occasion a dispute between two sets of work- 

 men ; pi. 25, fig 4. At the same mine the tin lodes are 



