Mount Brew, southwest of the resort town of Whistler, is a high lava dome composed of andesite or dacite that probably formed subglacially between 25,000 and 10,000 years ago. It contains two masses of rock that might resemble ice-marginal lava flows. These edifices have not been studied in detail but they could have formed during the same period as the Ember Ridge subglacial domes due to their structures, columnar joints and compositions.