(18) 
CHAPTER 6. 
No Metallic Veins. 
Tue bed of Plymouth Limestone appears to be 
entirely free from all Metallic Ves; and I have 
not seen, nor have I heard of any thing, tending 
to what Miners would call a Load, of any of the 
metals, having ever been discovered in any one of the 
quarries that have hitherto been opened. It is true, 
that indications of the presence of Jron, and also of 
Manganese may occasionally be seen, as a colouring 
matter, in particular spots; but always thinly spread, 
and never in any quantity. 
In a single instance, I have observed spots of 
Pyrites, in fragments of Limestone and slate, taken 
