The walls, or banks, of the channel have been denuded away, thus converting the pitchstone casting into a projecting wall of rock.
But there ain't no crawlin' out o' pitchstone Canyon, they say.
In the south of the island there are sills and dykes of felsite, quartz-porphyry, rhyolite, trachyte and pitchstone.
The lavas are curious from abounding in, or rather being in parts composed of pitchstone.
I strongly suspect the underlying granite has altered such beds into this pitchstone.
And she mighty near rolled off down into pitchstone Canyon, comin' up by the cut-off trail.
Such media are the volcanic rocks when they are rapidly cooled, producing various kinds of pitchstone, obsidian, &c.
The trachytes occupy a position between the pitchstone lavas on the one hand, and the andesites and granophyres on the other.
I was glad enough, though, when we struck the parklike levels of the pitchstone plateau as the scene of our further progression.
I have brought from that locality a single specimen of pitchstone, perfectly resinous, bleak and shining.