CHAPTER VIII.. Sand and Gravel of the Boulder--What They Suggested--Their

Sand and gravel of the boulder--What they suggested--Their consideration leads us among the more mechanical operations of Nature--An endless succession of mutations in the economy of the universe--Exhibited in plants In animals--In the action of winds and oceanic currents--Beautifully shown by the ceaseless passage of water from land to sea, and sea to land--This interchange not an isolated phenomenon--How aided in its effects by a universal process of decay going on wherever a land surface is exposed to the air--Complex mode of Nature's operations--Interlacing of different causes in the production of an apparently single and simple effect--Decay of rocks--Chemical changes--Underground and surface decomposition--Carbonated springs--The Spar Cave--Action of rain-water--Decay of granite--Scene in Skye--Trap-dykes--Weathered cliffs of sandstone--Of conglomerate--Of shale--Of limestone--Caverns of Raasay--Incident--Causes of this waste of calcareous rocks--Tombstones,

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