The Slate Islands are a small archipelago in Lake Superior, Ontario, Canada, about south of the town of Terrace Bay. The island group, consisting of 15 islands in total, was created by a meteorite impact which formed a crater about wide. In 1985, the Ontario government established the Slate Islands as a natural environment provincial park. The islands are notable for having Ontario's largest herd of boreal woodland caribou. Geography The island group consists of two main islands (Patterson and Mortimer), five minor islands (McColl, Edmonds, Bowes, Delaute and Dupuis islands) and numerous islets. The total surface area is about . The nearby Leadman Group of islands, about east, is often considered part of the Slate Islands. This group includes Leadman, Cape, Spar and Fish Islands. Human history Human sites have been found on the islands dating to about 1000CE. A lighthouse was built on Patterson Island, the largest island, in 1903 to help ships locate the harbour at the nearby town of Jackfish, Ontario. The island is named after William Patterson, a former lieutenant-governor of Saskatchewan. Later, a fishing station was built on McColl Island. The original forests on the islands were modified by logging and forest fires. Up until the 1940s, the islands were used to stockpile boomed logs from the mainland Lake Superior north shore for export on lake freighters to pulp mills in the United States. In 1985, the Slate Islands were protected as an Ontario Natural Environment Provincial Park. The islands remoteness is enforced by almost of open, wild, Lake Superior water and its distance from any large communities. It is frequented by naturalists, fishing parties, sailors exploring this Great Lake, and recently by an increasing number of sea kayaking parties. Fauna The islands are home to woodland caribou which migrated by ice bridge from the mainland most recently in 1907. They have been studied extensively from 1974 to 2007 by Dr. A.T. (Tom) Bergerud. The caribou are a classic example of island biogeography in action; the islands are notable for species that are absent but present on the adjacent mainland (red squirrel, moose, white-tailed deer, and grouse). No ungulates were present on the islands until the caribou arrived in the early 1900s while predators have been present only sporadically. Caribou reached the highest population density in the world on the islands before the 1990s, with the herd estimated at 650 animals. After a food