Benue Trough the Central African Shear Zone and for the volcanic island of St. Helena in the Atlantic ocean. Three periods of magmatic activity (volcanic action) have been identified, 147–106 Ma, 97–81 Ma and 68–49 Ma. The first is prominent in the north of the trough, and contemporary with magmatism in Brazil, probably occurring during a period of crustal extension before the Atlantic started to open. The second is found only in the south of the trough, and may belong to a period when the extension of the Atlantic had slowed down, ending with a period of compression. The third and last
The Trough a "true whitewater run" (difficulty level = Class I-II). It is, however, a markedly beautiful stretch of river. The Trough General Store in Glebe at The Trough's mouth offers canoe rentals and shuttles canoers and kayakers to The Trough's opening near McNeill in the South Branch Wildlife Management Area. Several primitive campsites are accessible along this stretch. The area is well known as a habitat for bald eagles, hence its Potomac Eagle Scenic Railroad sightseeing train on the SBVR. Visitors can board the train at Wappocomo Station on West Virginia Route 28 in Romney. The Trough The Trough is a