VI.—Miniature Domes in Sand

Extract

In walking along a stretch of very fine smooth sandy shore at Blundellsands, I was very much struck at finding a portion of it studded over with numerous bosses of sand from ½ in. to 3 inches in diameter. Wondering what could be the cause of this singular phenomenon, I dissected some of them with my knife, and found in all cases a cavity below corresponding in extent and height to the external form of the boss or tumescence. The perfect regularity and smoothness of these protuberances was very remarkable; they appeared to be in all cases segments of spheres connected with the plane of the shore by reflex spherical curves. The largest I dissected measured 3 inches in diameter rising half an inch. The thickness of the dome was ½ an inch and the cavity below was 3 inch diameter also. The following is a section—