There are other submarine mines in the neighbourhood of Botallack. In Little Bounds and Wheal Cock the hardihood of the miners tempted them to follow the ore upwards, even to the sea; but the openings made were very small, and, the rock being extremely hard, a covering of wood and cement in the former, and a small plug in the latter mine, sufficed to exclude the water, and protected the workmen from the fatal consequences of their rashness. ‘In all these, and in Wheal Edward and Levant,’ says Mr. Henwood,[47] ‘I have heard the dashing of the billows and the grating of the shingle overhead even in calm weather. I was once, however, underground in Wheal Cock during a storm. At the extremity of the _level_ seaward, some eighty or one hundred fathoms from the shore, little could be heard of its effects, except at intervals, when the reflux of some unusually large wave projected a pebble outward, bounding and rolling over the rocky bottom. But when standing beneath the base of the cliff, and in that part of the mine where but nine feet of the rock stood between us and the ocean, the heavy roll of the large boulders, the ceaseless grinding of the pebbles, the fierce thundering of the billows, with the crackling and boiling as they rebounded, placed a tempest in its most appalling form too vividly before me ever to be forgotten. More than once, doubting the protection of our working shield, we retreated in affright, and it was only after repeated trials that we had confidence to pursue our investigations.’ Footnote 47: ‘Transactions of the Royal Geological Society of Cornwall,’ vol. v. p. 11. It seems that at times of great storms, even the miners, accustomed for years to these submarine caverns, have been terrified by the roaring of the sea. They have heard, as it were, mountain dashing against mountain, or as if all the artillery of England was booming over their heads. Yet their roof of rock, thin as it is in some parts, has hitherto shielded them against the sea, and will no doubt continue to defend them against it. On leaving these wonderful submarine excavations, the scenery of the upper world appears doubly beautiful.