To my ears, this placement of false dawn in the West is a symbolic comment on the thwarted promise of America. Note that what thwarts the dawn is "the shade of the mountains," symbolizing the vast shelter of the Ideal. Conrad's geographic construction of Sulaco is deeply symbolic: situated in the optimism of false dawn, it persists in a twilight of idealism that is portrayed as simultaneously deepening and retreating, to be suddenly replaced by total disillusionment in the form of the noontime sunrise from behind the mountains.