The quarry itself, as already stated, was opened in the face of the cliff, at a point where the successive beds of solid rock seemed to promise the fairest prospect of success. The preliminary operation was to remove a very thin alluvial cover which scarcely concealed from view a large mass of most beautiful granite, whose reddish colour is said to have given the name of _Ross_[19] to that part of Mull, the shores of which everywhere exhibit massive slopes of that fine rock. The granite is separated very abruptly from the basalts of the surrounding district, so as to leave the Ross purely granitic; but in no part of the whole coast, which abounds with creeks and bays, does the rock appear to be of equal quality, or so conveniently situated for shipping, and so easily accessible to quarriers, as at the spot we had chosen. I know of no instance of a quarry so fully answering the most sanguine expectations as that of the Ross of Mull; and I have never seen a granite quarry of equally great resources, as regards both the quantity and the quality of the material produced. The rock in general yielded easily before well-directed shots, and was separated into large masses, capable of being advantageously cut, with little loss of material, into shapely blocks, by means of wedges, which work remarkably well in that rock. A few weeks after the quarrying operations had been commenced, a single shot detached 150 tons of excellent stone, in the cutting of which into blocks for the Lighthouse Tower little loss of material occurred; and in the course of the season of 1839, although the summer was chiefly spent in the preliminary works above noticed, the Mull quarries produced nearly as much workable material for the Lighthouse Tower as the Hynish quarries had done in three years. In the course of the future working of the quarry, when it came to be more fully opened, its resources were so great, that on one occasion a single shot shook about 570 tons, while another shot detached a mass of 460 tons. In that way, between April 1839 and June 1840, material had been quarried in that single spot, sufficient to supply 4300 selected blocks, varying in weight from ³⁄₄ ton to 2¹⁄₂ tons each. The average monthly produce of the quarries was about 400 tons, and there were generally employed in them 26 quarriers, 3 labourers, and 2 smiths. The quantity of gunpowder consumed in the quarry was small, as it was almost exclusively employed in great bores about 11 feet deep, for the purpose of detaching large masses which had no _open side_ and could not be removed by means of the _pinch_ or _crow-bar_. When a mass of rock had been thus removed, it was cut up into various portions by means of wedges, and finally subdivided into blocks, _hammer_ (or as it is called _quarry_) _dressed_, according to rough moulds, whose dimensions exceeded those of the stones of the various courses of the building by a quantity which was considered