This yellowish conglomerate can be traced along the cliffs for more than a mile, when it descends below the sea-level at the solitary stack of Bod an Stòl. A few hundred yards further west, what is probably the same band appears again at the base of the precipice overlain by prismatic basalts. But the conglomerate, here only 12 feet thick, is made of much finer detritus which, largely composed of volcanic material, includes small well-rounded and polished pebbles of Torridon Sandstone. Beneath it lies a bed of dark shale, with remains of plants, resting immediately on a zeolitic amygdaloid which plunges into the sea. The chief interest of this locality is to be found in the shale which, instead of being at the top of the sedimentary group, lies at the bottom. I was informed by Mr. A. Thom that leaves had been obtained from this shale; but I was not successful in my search for them. The locality is only accessible by boat, and, as the coast is fully exposed to the Atlantic swell, landing at the place is usually difficult and often impossible. About a mile and a half still further west, where a foreshore fronts the precipice of Earnagream at the Camas Tharbernish, a band of intercalated sedimentary material underlies the great escarpment of basalts and rests upon the slaggy sheet with the singular surface already referred to (p. 187). This band not improbably occupies the same platform as the upper conglomerate of Compass Hill. It is only about seven feet thick, the lower four feet consisting of a dull green pebbly tuff or ashy sandstone, with small rounded pieces of Torridon Sandstone, while the upper three feet are formed of dark shale with crowded but indistinct remains of plants. Here the more usual order in the sequence of deposition is restored. The shale is indurated and shattery, so that no slabs can be extracted without the use of quarrying tools. [Illustration: Fig. 270.--Section of shales and tuffs, with a coniferous stump lying between two basalt-sheets, Cùl nam Marbh, Canna. ]