What Fitzgerald calls "the valley of ashes" is located midway between West Egg and New York. It is the dumping ground for the trains that bring furnace ashes out of the city. A "small foul river" borders one side of the site. This is a place of gray, powdery dust that fills the air and blots out the sun. Fitzgerald describes it as "a fantastic farm where ashes grow like wheat into ridges and hills and grotesque gardens," referring to the mountains of ash that have collected here after being dumped. He also describes the men who shovel the ashes out of the railroad cars:
Occasionally a line of grey [railroad] cars crawls along an invisible track, gives out a ghastly creak and comes to rest, and immediately the ash-grey men swarm up with leaden spades and stir up an impenetrable cloud which screens their obscure operations from your sight.
This place of industrial dust and grime stands in sharp contrast to the bright beauty of the homes in West Egg, and by inference, in East Egg. George Wilson's gas station is located here, as well as the decaying billboard with the eyes of T.J. Eckleburg watching over all.
The valley of ashes symbolizes the by-product of industrial wealth. It represents a garbage dump, a place the wealthy can dispose of its sin and indiscretions. It is a dirty,dusty, hopeless place that exists between the 'palaces' of the Eggs and the heavenly city of New York. What I think is most powerful regarding Fitzgerald's description of the valley is not just its physical appearance, but how George and Myrtle are treated by Tom and Daisy Buchanan. George and Myrtle are also the creation and the by-products of wealth, and in that sense can be used or discarded as the Buchanans see fit. The climax of Fitzgerald's commentary on the valley of ashes are those blind eyes that look down on the valley everyday but cannot see the destruction taking place right in front of their eyes.