138 Mr. William Phillips on the Veins of Cornwall. 



completed an account of it, to present it to the Geological So- 

 ciety. 



In describing that effect produced by the interruption of one 

 vein by another, called the heave, it ought to be noticed that a 

 copper vein going down with a quicker underlie than a tin vein, 

 always passes through it, and sometimes interrupts its regular course. 

 And if the underlie of the copper vein be south, and that of the 

 tin vein north, or vice versa, the copper vein continues its course, 

 but interrupts that of the tin vein, heaving it out of its first direc- 

 tion ; and although Pryce has merely given the appellation of 

 ' Gossan' to those veins that heaved the tin veins, as just noticed, 

 it seems to me probable that these ' Gossans' were veins containing 

 copper, which is rendered the more so, as the term ' Gossan' is 

 frequently given to a copper vein, merely from its being the pre- 

 vailing substance. The heave of a tin by a copper vein was, I 

 believe, one of the remarkable and complicated disasters which 

 befel the veins in Huel Peever. 



Feeder. 



A small metaU'tferons vein or string is sometimes found to take 

 the same course as the east and west vein, (PI. 6. fig. 3. ) When its 

 underlie is so much quicker than that of the latter, as to overtake 

 it in going down, the metalliferous vein is generally found to in- 

 crease in size, not merely in the proportion of the addition of the 

 lesser vein, but very much more, so as to make a great body of 

 ore, called by the miner a gulph of ore at their junction. This 

 species of vein is therefore termed a Feeder. 



Leader, 

 Wh'le working in the course of a load, small metalliferous 



