The Oronto Group is a thick group of arkose sandstone and shale located beneath the Bayfield Group in northern Wisconsin, along the northwestern side of the Keweenaw Peninsula and southern Isle Royale, and believed to extend into Minnesota. Because it is almost entirely red in color and highly tilted, it is considered separate from the Bayfield Group. The Oronto Group is divided into the Copper Harbor Conglomerate, Freda Sandstone, and Nonesuch Shale. As the group is devoid of fossils, its age is difficult to ascertain, though it may be of Keweenawan Age.
Explore contextually related video stories in a new eye-catching way. Try Combster now!