P.S. "Sheet piles" are those sheets of metal which were driven into the ground to a depth of up to 30 feet and which encompassed the site of the Aomon crypt. (In fact, buckling of the pilings toward the end limited the depth of the excavation. The pilings interlocked and were made of 3/8" steel, were 18" in width, and varied from 15-30' in length. The pilings facing the water were left in place; those outlining the other three sides of the crypt were removed and decontaminated for use elsewhere. )