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
Thousand Islands Parkway Thousand Islands Bridge. It continues northeast, serving the riverside communities of Darlingside, Rockport, Narrows, La Rue Mills and Mallorytown Landing. At Butternut Bay, the Thousand Islands Parkway merges into Highway 401 eastbound and a left-hand exit provides access to the parkway from westbound Highway 401. Throughout most of the length of the parkway, a recreational trail parallels to the north. The Thousands Islands Parkway follows what was the original alignment for Highway 401. However, because of the residential properties and the scenic nature of the route, a new inland route was constructed through the mid-1960s. The recreational trail follows the