The grauwacke slate appears on the right or eastern bank of the Heyl, and continues without interruption as far as Redruth. Nevertheless, we are upon its boundary near Camborne, and I should not be surprised if that place, which lies a little to the right of the road, were on granite, for the ground rises in that direction, and at a small distance the Tors make their appearance. I had already observed the grauwacke at several places on the Bristol Channel, but it was of so small extent, that I found it impossible to judge, whether, according to my expectations, the strata dipped N.W. on the northern slope of the chain. There was every reason to expect that this would be the case, as the strata on the opposite side of the chain, have, as I have shewn, the contrary slope; I was therefore much gratified when I found my expectation realized in the course of an excursion I made from Redruth to Portreth, the nearest seaport, and three miles to the N.N.W. I had at the same time a very agreeable walk, and it is the only place where, in this part of the country one could forget for an instant, being in the midst of a mining country, and I may also say in the midst of ruins, for between Camborne and Scorrier House, there is hardly any vegetation to be seen. The ground is on all sides torn up and covered with rubbish and excavations.
In order to go to Portreth, we follow the course of a brook, along the sides of which there are some stream works: the country gradually lowers, and the verdure of the meadows foretold the approach of the sea, which we very soon discovered, and as we went through a narrow and woody pass, it had quite the appearance of a lake. When we reached the bottom of the bay, we found the grauwacke fully displayed; the angle which its strata make with the horizon is nearly the same as that which was formerly mentioned.
