The Grimpen Mire was in the county of Devonshire, the residence of the Baskerville family. The moors had a sublime beauty of its own, filled with undulating downs, long green rollers and crests of jagged granite foaming up into surges. One could not be tired of exploring the moors or fathom the wonderful secrets it contained. It was a vast, barren and mysterious landscape.
Stapleton revealed that the bright green spots which were scattered thickly over the moor and seemed more fertile than the rest was actually the Grimpen Mire. A false step would signify death to man or beast. Then narrated an incident about how he saw a pony wander into one of those and it never came out. He saw its head for quite a long time craning out of the bog-hole but it sucked down the pony eventually. Even in the dry seasons it was a danger to cross but after the autumnal showers, it turned into a dangerous quagmire.Only Stapleton knew how to find his way to the very heart of the mire and return alive, penetrating into the deepest recesses of the bog.
Stapleton's apparent objective was to establish his false identity as a naturalist. The islands that lay beyond the moor and were cut off on all sides by the impassable mire contained rare plants and butterflies if one could reach them. It was his aim to reach those places because as a naturalist it comprised his work to go in search of rare species. He wanted Dr Watson to believe what he presented as the truth about his existence.