Ripogenus Gorge

Ripogenus Gorge
1870s view of Ripogenus Gorge
Length	10 miles (16 km)
Width	700 feet (210 m)
Geography
Location	Northeast Piscataquis, Piscataquis County, Maine, USA
Coordinates	45°52′33″N 69°09′00″W / 45.8759°N 69.15°W / 45.8759; -69.15
Rivers	West Branch Penobscot River

Ripogenus Gorge is a rock-walled canyon formed in Maine where the West Branch Penobscot River crosses the Caribou Lake anticline. Ripogenus Falls controlled discharge from Ripogenus Lake until Ripogenus Dam was completed at the upstream end of the gorge in 1916. The dam forms a hydroelectric reservoir raising the level of Ripogenus Lake to include the upstream Chesuncook Lake, Caribou Lake, and Moose Pond. The resulting reservoir is often identified by the name of the largest included lake: Chesuncook. The gorge provides an unusual exposure of Maine North Woods bedrock typically covered by saturated glacial till. The Silurian Ripogenus Formation of weakly metamorphosed shallow marine siliciclastics and fossiliferous limestone has been described from investigation of the gorge.^[1]