The Eramosa River is a river in Wellington County in western Ontario which rises near Erin, Ontario, and flows southwest through the city of Guelph, where it joins the Speed River, which then enters the Grand River in Cambridge.
The river flows through an area covered with several hundred glacial potholes near Rockwood, one of the largest being the Devil's Well, 13.1 metres (43 ft) deep, 6.4 metres (21 ft) wide at the top and 4.9 metres (16 ft) at its base.
Coordinates: 44°36′N 81°06′W / 44.6°N 81.1°WThe Eramosa is a Silurian stratigraphic unit exposed along the Niagara Escarpment in Ontario and western New York State. In the late nineteenth century it was an important source of building stone in Hamilton, Ancaster and Waterdown, and in the late twentieth century quarries in a similar unit, also called the Eramosa, near Wiarton in the Bruce Peninsula, became an important source of dimension stone at a time when most of the other resources of similar stone were depleted. Work in these quarries led to the discovery of exceptionally well preserved fossils (the Eramosa lagerstätte). On the east Mountain at Hamilton, a well-developed cave system was discovered in the Eramosa and has now been designated as the Eramosa Karst Conservation Area.
Eramosa may refer to: