Pepper's Land is a idyllic subsurface paradise named after English naval sergeant, James Winston Pepper, who was lost at sea (in "emerald waters") in 1870. Pepper's Land was reputedly the source of a "garishly-coloured" phantom submarine and the home of a "malignantly species of blue dwarf or troll" that turns up occasionally in Argentina.
Pepper's Land and etc. are references to the Beatles film Yellow Submarine (1968). The "ghost submersible" is the Yellow Submarine. "James Winston Pepper" is the discoverer of Pepperland. The "emerald waters" is the Sea of Green. The "malignant species of blue dwarf" is the Blue Meanies. And their location, and the presence of the Blue Meanies in Argentina, is based on an exchange between the Chief Blue Meanie and his Second, Max: "It's no longer a blue world, Max. Where shall we go?" "Argentina?"