Earth in one of her gambols. Her slate panoply
gave way, parted from N.E. to S.W., and out burst
the granite, which had been kept under and was not
intended for show.
Her hooks and eyes gave way first of all in South Devon, and out swelled the great mass of Dartmoor. They held for a little space, and then out broke another mass that constitutes the Bodmin moors. It heaved to the surface again north of S. Austell, then was held back as far as Redruth and Camborne. A few more hooks remained firm, and then the garment gave way for the Land's End district, and, finally, out of the sea it shows again in Scilly.
Or take it in another way. Cornwall is something like a leg. Let it be a leg vested in a grey stocking. That stocking has so many "potatoes" in it, and each "potato" is eruptive granite.
Granite, however, likewise cracked, formed "faults," as they are called, in parallel lines with the great parent crack to which it owed its appearance, and cracks also formed across these; and through the earlier cracks up gushed later granite in a molten condition, and these are dykes.
Moreover, the satin body not only gave way down its great line of cleavage, but the satin itself in places yielded, revealing, not now the under-linen which boiled out at the great faults, but some material which, I believe, was the lining. So when the granite broke forth there were subsidiary rifts in the slate, and through these rifts a material was extruded, not exactly granite, but like it, called elvan. These elvan dykes vary from a few feet to as many