The nepheline syenites and pegmatites of Mount Royal, Montreal. QUE.

The volcanic neck or plug which forms Mount Royal presents a complex history of igneous activity. It comprises a varied and interesting group of rocks of plutonic and hypabyssal types, which penetrate gently dipping Ordovician strata. In common with most of the other Monteregian Hills there were two main intrusions, a basic followed by a more alkaline magma. [...