Taught by Philip Turner, David Thompson surveyed for the HBC in northern Saskatchewan and Manitoba before he transferred to the Northwest Company in 1797. Over the next 15 years he surveyed from Lake Superior to the Pacific and, during several years in the Cordillera, unravelled the complex drainage basin of the Columbia River. This is a detail showing the Sturgeon Weir River, Amisk Lake, Cumberland House, Pelican Narrows, Goose Lake, Goose River, and Cranberry Portage in Manitoba and Saskatchewan