The Fontaine Formation is mentioned by Clark (1959), but its detailed description is by Clark and Globensky (1976). The name refers to the Fontaine Quarry, along the Lard River, where the type section was described (NE corner of sheet 31I07).

According to Clark and Globensky (1976): The Fontaine Formation “consists of dark crystalline limestone, finely bedded and generally fine-grained. It includes a lot of argillaceous material, either in laminated beds or in irregular networks of veinlets cutting limestone. These argillaceous beds are very rich in bryozoans and inarticulate brachiopod debris. At the Fontaine Quarry and upstream, most of the formation consists of alternating bryozoan-rich beds (in which bryozoans are found in a flattened network of dark siliceous material) and dark bituminous limestone altering to blue and, in places, discreetly crystalline.”

Thickness and distribution

At the type section of the Fontaine Quarry, located along the Lard River north of Trois-Rivières, the Fontaine Formation reaches 2.5 m for over 800 m (Clark and Globensky, 1976). Just north of the Fontaine Quarry, the formation forms a thin band (~300 m wide) slightly curved extending almost 35 km between the Saint-Prosper Fault, to the east and Saint-Cuthbert Fault, to the west (north of sheet 31I07 and SW corner of sheet 31I09) (MNRF, 2009a, b; Thériault, 2014).

Dating

None.