A screen in which each section of the deck is flatter than the preceding one. The rate of feed is reduced on succeeding sections to maintain proper bed depth for rapid 3386 stratification. It is designed for fine dry screening of 3/4-in (19-mm) by 0-in, 1/2-in (13- mm) by 0-in, and 1/4-in (6 mm) by 0-in moist coal or other material.