FREMONT ISLAND — MUD ISLAND. 163 



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 gra- 

 dual 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 slate 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. 



Thursday^ 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 skifi" 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 



