Note 235 — Chapter XXII

I have repeatedly, and equally in vain, sought for scratchings on many of the most conspicuously moutonneed gneiss rocks of Switzerland. The retention of such markings depends on other circumstances than the mere hardness of the rock, or amount of aqueous action. What can be more astonishing than to see these most delicate scratches retained in all their sharpness on rocks clothed with seaweed and shells, and exposed at every tide, in the bays of western Scotland!