This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
Drain walls shall be constructed as shown on the plans or ordered. The stones used shall be clean, hard limestone of proper size or other suitable material laid in horizontal courses and well bedded and bonded. The drain walls will be paid for by the cubic yard.
Trench excavation will be paid for separately.