THE buoyancy experienced during the first week of the Keeneland September Yearling Sale, which featured Books 1 and 2, carried on when the sale resumed last Saturday following a one-day break. The session was topped by the sale of a colt by Pioneerof the Nile for $525,000 to Steven Young. Keeneland sold 253 yearlings for $31,392,500 on Saturday, for an average of $124,081 and a median of $100,000.