The Insular Belt includes rocks exposed in the mountain ranges of Vancouver Island, the Queen Charlotte Islands and the Alexander Archipelago in the Alaska Panhandle. In addition to these island mountains, it includes the rocks flooring the submerged regions of the continental margin. The belt extends as far west as the toe of the continental slope, about 100 km west of Vancouver Island. It is made of volcanic and sedimentary rock, together with intrusions of granitic rock. Most rocks in the southern Insular Belt formed between mid-Paleozoic and early Mesozoic time (between 350 and 180 million years ago), although sandstones mostly on the east side of Vancouver Island and submerged below the water around the island, and local igneous rocks, are mainly of Late Cretaceous and early Tertiary ages (85-40 million years). Deposition of sediments in the belt continues, with the submerged regions receiving detritus from major rivers, such as the Fraser River near Vancouver.