superadjacent

Conversely, if it be assumed that the superadjacent material is composed of large bowling balls, interlocking with some degree of regularity, it can be seen that those above will form themselves into an arch over the "centering" made up of those supported directly by the roof of the structure, thus relieving the structure of any load except that due to this "centering."

Pressure, Resistance, and Stability of Earth American Society of Civil Engineers: Transactions, Paper No. 1174, Volume LXX, December 1910 J. C. Meem