186 



ON THE MINERAL AND METALLIFEROUS [Ch. IX. 



" For example, in Huel Friendship Mine (near Tavistock, 

 Devon, situated in schist), as shown in the annexed plan, 

 the lode bears 20 N. of W., dipping N. about 55, and the 

 cross-course a, 10 E. ofW. W. - 75 



b, N. and S. - 50 



c, 35 E. of N. - 70 

 These cross-courses all heave the lode towards the left hand ; 

 the first two towards the smaller, and the third towards the 

 larger angle : but all of them have produced heaves of various 

 extent. Thus, 



The cross course a has heaved the lode 2 1 fathoms, 

 b 17 



c 3 



Fig. 20. 



Huel Friendship Mine. (Ground Plan.) 



In this case all the heaves are in the same direction ; but 

 sometimes, as in Weeth Mine, recorded by Mr. Carne, the 

 lode is heaved to the right by one cross-course, and to the 

 left by another ; and, in both, the heave is towards the larger 

 angle." An illustration of the intersection of one vein by 

 two flucans has already been given in fig. 17., taken from 

 Huel Jewel mine. " The dotted lines denote the variable 

 quantity of the dip at different depths : and it will be seen 

 that both flucans heave the lode, the amount of the heave 

 varying very much in the case of each flucan, but more 

 especially in the eastern one, as indicated by the distance 

 between the ends of the continuous lines on the opposite 

 sides of the dotted lines. In the same plan, there are separ- 



