Abstract: An elongated trough having front and rear ends and including a pair of upstanding opposite side flanges interconnected along their lower marginal edge portions by means of an integral bottom wall extending therebetween is provided. The flanges are convergent toward the rear end of the trough and the bottom wall tapers toward the rear end of the trough. The flanges are upwardly divergent and taper in height toward the front end of the trough. A rear wall extends between and is secured to the rear ends of the flanges and the rear marginal edge of the bottom wall and the rear wall terminates downwardly in an integral horizontally outwardly extending flange projecting outwardly from the rear end of the trough and disposed coplanar with the bottom wall of the trough.