form a consolidated fibrous mat 18 that point of mat consolidation is observed on the paper machine as a 34 dry line 34 zone 17 thus formed the mat is further dried by pressure and heat to an integral continuous paper web in transit the pond 16 is laterally confined by deckle structure such as the screen edge cupping rail assembly and the deckle board assembly 40 the screen edge cupping rail assembly comprises the rail element 21 having a concave inside surface 22 for supporting a lateral edge of the traveling screen 12 the 34 inside 34 orientation refers to the rail side most proximate of the screen 12 and the stock pond 16 the top of rail 21 is crowned with a plurality of flushing fountain sections 23 each about 18 to 24 inches long each fountain section comprises a square or rectangular section fluid conduit 24 and a side plate 25 the fluid conduit 24 provides a flat top surface penetrated by a row of holes between the upwardly projected inside surface of side plate 25 and the weir edge of the top surface flushing fluid is supplied through independent conduits 32 holes 27 may have an alternating bore axis oritentation with the axis of odd holes aligned at substantially 0 u00b0 with vertical and the axis of even holes set at an angle of 15 u00b0 to 45 u00b0 from vertical.