Cox was an avid writer and wrote heavily on forestry, nature, and conservation topics. Cox contributed a recurring column in the magazine The Farmer and exerts of which were later published as Wild Animals of the Field and Forest and, with coauthor Dietrich Lange, Bird Stories. Cox is perhaps best known today for his collection of folkloric sketches, Fearsome Creatures of the Lumberwoods, with a Few Desert and Mountain Beasts, a chief literary resource on fearsome critters of North American folklore.
