The Spences Bridge Group is a 100-million-year-old volcanic group of the southern Intermontane Belt in British Columbia, Canada. It consists of two stratigraphic units known as the Pimainus Formation and the Spius Formation. The Spius Formation represents a shield volcano and the underlying Pimainus Formation is interpreted to be a set of stratovolcanoes.
References
Spences Bridge Group Wikipedia(Text) CC BY-SA