Metalliferous Veins. 163 



cides with the facts. In Cardrew Downs, Wheal Trenwith, and' 

 WhealBol ton, parallel lodes with different underlies are heaved the 

 same way, by the same cross-course. Such things, with a ver- 

 tical motion, are totally at variance with it. But let us see if 

 oblique motion will help us : At Dolcoath (a beautiful fact 

 kindly pointed out to me by Captain Petherick) an elvan 

 course and two veins dip northward ; all three are traversed 

 by a cross-course, the two teins are heaved different distances 

 but loth to the right ; and one of them is heaved from the Tcillas 

 into the elvan , whilst the elvan itself is not heaved ; whilst still 

 continuing northward the same cross-course is itself heaved by 

 an east and west vein. It is clear that an oblique motion on 

 the line of the dip of the unheaved vein (the elvan) will not 

 satisfy all the conditions. 



In the same mine the same intelligent gentleman describes a 

 case recorded by Mr Fox, where one lode heaves another at one 

 depth, whilst, at a different one, it is itself intersected by the 

 same vein which it had hove. 



Slides are supposed to be the results of similar movements 

 shewn on a transverse section, and primdjfiici, the want of co- 

 incidence is far more striking. But have we any greater evi- 

 dence of mechanical disturbance than in the preceding case ? 

 In the well known section of Wheal Peever we have one case 

 of the vein in the hanging wall being the lower > and two of the 

 same wall being the higher. In Mr Garners section of Tresf- 

 kerby, the hanging wall, in four cases, seems the higher; whilst 

 in Trevannance (from the same authority) we have five cases 

 of the contrary. In Herland there is a fine case of the foot 

 wall being the lower, and in South Wheal Towan, where the 

 contrary obtains, the slide in one spot is split into two, and a 

 portion of the vein is contained between them ; whilst, above 

 and below, these unite and form one vein only. There appears 

 no greater harmony here than in the cases of heaves. 



Professor Phillips well remarks, " It is, besides, no argu- 

 ment for one theory that another is beset by difficulties which 

 are left unexplained in both." Having, however, stated these 

 objections to the prevailing theory, it is not the point at issue 

 for its advocates to shew that any hypothesis I may have, if I 

 have one, is equally objectionable ; but it is for them either to 



