On the eastern side of Howe Sound lies the southernmost zone of volcanic activity in the Garibaldi chain. This zone, known as the Watts Point volcanic centre, is a small outcrop of volcanic rock that is a portion of a subglacial volcano. The outcrop covers an area of about and an eruptive volume of roughly . The location is heavily forested and the BC Rail mainline passes through the lower portion of the outcrop about above sea level. It represents a feature in the Squamish volcanic field.