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remarkable not to be recognized imme-diately as that which occurs in situ in theValorsine.

Of the blocks of Gneiss found on theJura , some are traced to the foot of Eigers,others to the mountains between SemBranchier and Martigny .

The blocks of black Limestone andGreywacke are traced to the mountains ofAigle, the Dent de Midi, and the Dentde Morcles.

Those of Jade and Smaragdit, occur-ring near Lausanne , near Maudon, andthe lake of Neuchatel, to the Val de Bagne,above Sem Branchier ; those of serpentinein the same neighbourhood to the Glacierof Durand.

The grey weather stones, so plentifullyscattered over the southern counties ofEngland, are evidently derived from thedestruction of a rock which once lay overthe chalk. Gravel may, in like manner, betraced in most instances, to the beds wdiichsupplied it. The flint gravel about London is derived from two sources at least: it isin part supplied by the attrition of flints