sentences:  Isolated by geology behind the rugged Canadian Shield and many hundreds of miles of wilderness, settlers and their neighbours had access to outside markets and sources of supply only by two water routes.The first, maintained by the Hudson's Bay Company (in which Lord Selkirk was a principal investor), was a sea route from Great Britain to York Factory on Hudson Bay, then up a chain of rivers and lakes to the colony, 780 miles (1250 km) from salt water to the Assiniboine.The alternative was the historic route of the rival North West Company's voyageurs from Montreal through Lake Huron to Fort William on Lake Superior.