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Show FREMONT ISLAND- MUD ISLAND. 168 The west point of the island presents a bold escarpment, one hundred feet in height, of talcose slate, overlaid by granite and gneiss, occasionally traversed by seams of white ferruginous quartz, and containing cubic crystals of iron pyrites. The ascent of the southern slope of the island in this part is much more gradual than from the western point where we first landed, and a beautiful beach, covered with clear, white quartz pebbles, lined the shore of a pretty little bay, now glistening in placid beauty under the rays of the setting sun. The slope on this side presents the same appearance of benches or lines of what must have been water levels or beaches, parallel and horizontal, though apparently not so near to each other as on the north side. Ledges of mica and talcose Blate crop out at different heights, with a dip to W. N. W. of about 40°. The slate is soft, slightly unctuous: laminae regular, parallel, and quite thin. At some twenty feet above the water, I observed two protruding ledges, in which, lying upon the slate, ( which in this case was of a much lighter colour than the rest,) was a dark- brown rock, much vitrified, tinged with iron, and burned so hard that it sounded, when struck, like delf- ware. It had, while in a state of fusion, flowed around the neighbouring rocks, forming a sort of mould or casing over them. These having perished by gradual disintegration, have left the moulds connected, but empty. In this lava, quartz, some white and some tinged with iron, is freely interspered; in some of the moulds, occasionally seamed with the white quartz veins, was a brown, hard sandstone, which, where exposed, was rapidly disappearing. The vegetation on this side of the island was similar to that on the other: the bunch- grass was especially fine and abundant. After a long and fatiguing row, reached camp at nine o'clock at night. Thursdatjy April 11.- Morning bright and warm, with gentle breeze from the south. Got under way early, for the purpose of putting up a station on Mud Island, distant about eight miles. A line of soundings was run until midway, when the boat grounded on a shoal which extends quite to the northern extremity of this part of the lake. The deepest water found on the line was eleven and a- half feet. The skiff was sent ahead with an officer, but it was soon left on the flat, and the party waded through soft mud and water to the shore. After dragging the large boat half a mile, a sufficiency of water was found to float her, within a hundred and fifty yards of a point |