Mr. William Phillips on the Veins of Cornwall. 137 



Heave. 



But when the underlie of this species of vein is in opposition to 

 that of the metalliferous vein, the effect of it is immediately the 

 reverse of that of the Slide, and is called the Heave. Pryce has 

 noticed a remarkable instance of this which occurred in the Goon 

 Laz and Pink tin mines, in the parish of St. Agness. The tin 

 load underlaid north, the gessan vein south. (PI. 7. fig. 7.) At 

 62 fathoms in depth, it separated the tin load at a, heaving the 

 other part of it up to b^ 22 fathoms in perpendicular height, and 

 19 fathoms horizontally north. Another gossan vein afterwards 

 cut the tin load at r, heaving it up to d. The tin load then 

 resumed its course, until another gossan vein separated it at <f, 

 heaving it up iof. 



It will be observed that the effect of the heave is that of affording 

 a greater portion of the tin load at a given depth from the surface, 

 than would have been the case had the vein pursued its regular 

 downward direction. But this is not always a compensation to the 

 rniner ; for the vexation and expense accruing to him in searching 

 for the tin vein generally exceed any advantage to be gained by 

 the heave. It was, I beheve, principally the effect of a heave that 

 baffled the skill and experience of the most eminent practical miners 

 in Huel Peever j in which mine they vyere, during about 40 years, 

 in search of the load, and which was at length discovered. Per- 

 haps the history of that mine, and of the long and vexatious 

 search, occasioned by the loss of the vein, v/ould prove the most 

 satisfactory evidence that can be obtained of the strange pheno- 

 mena occasioned by the heave ; and I have the satisfaction of 

 knowing that it is the intention of a gentleman, who has nearly 



Vol. II. s 



