A patented pile formed by driving a steel shell into the ground to the required depth, putting in small quantities of concrete, and hammering them down so as to force the concrete into the earth beyond the point of the shell; thus enlarging the end and greatly increasing the bearing area, is called mac-arthur piles. The shell is afterward withdrawn gradually, as the hole that it made is filled with concrete. If the shell were left in, the method would be far more satisfactory; as the shaft of the pile is liable to be seriously imperfect. Same as pedestal pile.
Such pilings, of course can only be driven into mud, sand or clay bottoms. The author suggests the pile would be more effective, were the steel casing to be left in place – which suggests that this sort of pile would only be used where the cost of supplying enough casings for all the piles would be higher than the additional labour involved in extracting the casins.