CN-12-201-323NA Klamath Project - Oregon-California. Close-up view of rock pocket in left closure slot at elevation 4793. Concrete contained only coarse aggregate with a light coating of mortar. A large amount of clay was evident coating the aggregate as well. Removal was stopped at 2k inches although no firm concrete was found; November 1973; Bureau of Reclamation photo by J. A. Renning