Thousand Islands – Frontenac Arch is one of four ecoregions of the Mixedwood Plains. The Thousand Islands in the Saint Lawrence River have a distinctive flora and fauna and are a part of the biological corridor. The bedrock is mostly gneiss, granite and marble, more than a billion years old. The Frontenac terrain is the youngest of the Ontario portions of the arch, dated at 1.2 billion years old. These rocks were once part of a large mountain chain of the ancient supercontinent of Rodinia. There is also a meteor crater near Holleford, where the shield meets the limestone plains of southeastern Ontario. The area
Ten Thousand Islands Islands, south of Everglades City, is in Everglades National Park. The 99-mile long Wilderness Waterway begins at Everglades City and ends at Flamingo at the southern tip of the Florida peninsula. Administrative control of the islands is split between Collier County and Monroe County. The Ten Thousand Islands were used and occupied by Native Americans for thousands of years. Evidence of former living sites can be found under as much as four feet of water. A number of shell rings and other shell complexes have been identified in or adjacent to the Ten Thousand Islands. The Horr's Island archaeological site