Rambles among the Channel Islands / by a Naturalist.

Date:
[1855?]
Catalogue details

Licence: Public Domain Mark

Credit: Rambles among the Channel Islands / by a Naturalist. Source: Wellcome Collection.

    141/402 (page 129)
    selves of this stone for the purpose of making various utensils. !Near the celehiated pass— the Coupee, the geologist will also find much to interest him. In particular, there is at this spot a vein of porcelain clay, ten or twelve feet in thickness, and extending across the direction of this narrow ridge. This seam is rendered conspicuous even from Guernsey, in conse- quence of its whiteness, and the contrast be- tween it and the dark rocks on either side of it. It is not white throughout, but is in many parts much contaminated by purple, red, and yellow oxides of iron. Veins of quartz also intersect it, and grains of the same mineral are found dispersed through it. Were there nothing else to distinguish this tall pass, the conspicuousness of the vein in ques- tion would render it the subject of attention to the most careless eye. The island of Brechou, or LTsle des Mar- chands, appears to consist chiefly of gneiss, and of the rocks belonging to that series. The lines of stratification are in many places very evident. The rocks are very abrupt -and of singular forn|^^ Between this island and Sark is an isolated rock, the summit of which is covered with grass, and occasionally affords pasture to a few sheep. From its position, with reference to the latter island, it may be taken to consist K