Black dogfish to the clade formed by the granular dogfish ("C. granulatum") and combtooth dogfish ("C. nigrum"). The black dogfish is a common species, with a wide but discontinuous distribution in the temperate waters of the Atlantic Ocean; its range abuts, but does not extend into, the Arctic Ocean. In the northeast, it occurs from Iceland to Sierra Leone, including the Faroe Islands, southern Norway, and the Rockall Trough and Porcupine Seabight off Ireland. In the northwest, it is found from southern Greenland and Baffin Island to Virginia, being particularly abundant in the Laurentian Channel, and may occur further south to the
The Trough Long Knob (1,725 feet) flanks the Trough. Sawmill Ridge ends at the mouth of the Trough at the point where Sawmill Run descends the ridge and joins the river. The communities of Sector and Glebe are located here to the west and east, respectively. The concrete piers of the old bridge that once carried Fleming-Sector Road (County Route 8/3) connecting these two communities are still visible here as well. A typical Trough canoe run ends at the Harmison's Public Access Site below the old bridge and behind The Trough General Store. The Trough is a popular canoeing/kayaking venue, although not