bedstone
nounUS /ˈbɛd.stoʊn/ · UK /ˈbɛd.stəʊn/
Etymology From bed + stone.
1
A large, heavy, flat stone used to support a column or similar member, or as the lower stone of an oil mill.
- After demolition the girders for half the new structure were erected on bedstones already built on the abutments behind the springings of the old arch.1941 February, “Bridge demolition by lifting”, in Railway Magazine, pages 74–75: