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.

    143/402 (page 131)
    of these rocks which form the coast line in this part of Jersey. A very fine rock of a similar nature is found in Boulay Bay, the mass of which is of a beautiful dark green. The well sunk in the tower hill of St. Helier’s passes through about from forty to fifty feet of decomposed syenite, and beyond this to the depth of about two hundred feet in syenite in its fresh state. In no part of any of these islands does there occur a fossiliferous bed. Lime is only dis- covered in small veins of calcareous spar, sel- dom exceeding six inches in breadth, and found traversing some of the rocks of the gneiss series in Guernsey, or filling the cavities of the argil- laceous strata in Jersey. In some places in Guernsey scanty and insignificant portions of the recent formations may be found dispersed upon the surface; but of organic remains, in the sense in which that term is properly under- stood, there are none. The mineralogy of these islands is interesting; but in consequence of the almost endless inter- mixtures and combinations of the simple minerals in the various rocks and veins, it is also com- I plicated. There are a number of varieties of I granite found in the various quarries worked on : the northern coast. The composition of this rock, it may scarcely need to be said, consists