In enlarging the works of the garrison, the military artificers frequently opened up cavities in the promontory which were mostly of sufficient interest to excite the curiosity of geologists; but one discovered in 1789, by some miners of the corps, while scarping the back of the Rock, attracted, at the time, unusual attention. It was situated about 160 feet from the foot of the cliff, on its eastern side, nearly under the Signal House, and its extent classed it among some of the largest within the area of the fortress. Removing the rank vegetation which had overgrown its mouth, a small chasm was bared, opening into a cave containing several chambers and grottoes, entered by narrow funnel-shaped crevices, some so low and winding that ingress could only be obtained by crawling through the long misty passages on all-fours. Seemingly, the roofs were supported by a number of pillars, which the dripping of ages had congealed into all shapes and sizes and into all degrees of hardness, from patches of soft silvered powder to the bold indurated columnar stalactite. On the floors, at different heights, were stalagmites, some peering up like needles, and others, swollen and grotesque, rose from frothlike cushions of delicate finish, which, “on being rudely touched, dissolved instantly into water.” The hall at the extremity was divided into two oblong recesses, floored by a “deep layer of vegetable earth,” where not a clump of the lowliest weed or a blade of grass was seen to show that vigour was in the earth.[67] Nothing seemed capable of living there but a colony of bats, some flapping about on lazy wing, and others torpid; no process to be active, but the cold one of petrifaction, which, in nature’s own confused method, had elaborated throughout the cavern, columns and pinnacles and cushions, puffs and concretions, some as fleecy as snow, others as crisp as hoar-frost, and others of an opal hue as transparent as crystal. All was rich, beautiful, and sparkling. It was a marvel to adventurers, but unfit for habitation; yet, in later years, this hole of the mountain was possessed by a Spanish goat-herd, who reached his solitude by the same threadlike but dangerous tracks as his goats. There might the recluse have lived till his bones fell among the petrifactions, but he was at length expelled from its gloomy precincts on account of his contraband iniquities. ----- Footnote 67: Martin’s British Colonies, 1835, p. 51-53. ----- 1779-1788. Colonel Debbieg’s proposal for organizing a corps of artificers—Rejected—Employment of artillerymen on the works at home—Duke of Richmond’s “Extensive plans of fortification”—Formation of corps ordered—Singular silence of the House of Commons on the subject—Mr. Sheridan calls attention to it—Insertion of corps for first time in the Mutiny Bill—Debate upon it in both Houses of Parliament.