Sand Pipe
or SAND GALL, in geology (plural), deep cylindrical hollows in a vertical direction found in England, France, and elsewhere, penetrating the white chalk and filled with sand and gravel. One seen by Sir Charles Lyell at Norwich in 1839 was 12 feet in diameter, and more than 60 feet deep. Mr. Trimmer attributed them to the action of the sea on a beach or shoal; Lyell to the chemical action of water charged with carbonic acid, derived from the vegetable soil and the roots of trees, on the chalk below.