Bull. U. S. B. F., 1917-18. 



Plate; XXVIII. 



Fig. I. — Barge with long crowfoot bars, employed on the Ohio River. Note rollers set on ends of bars to facilitate movement 



over the bottom. (See p. 51.) 



Fig. 2. — Lowering the crowfoot bar into the water, Ohio River. (See p. 51.) 



