Along the northeastern shore of Howe Sound is a small outcrop of volcanic rock known as the Watts Point volcanic centre. It is the southernmost volcano in the Garibaldi Volcanic Belt, comprising about of hornblende, pyroxene and sparsely porphyritic dacite lava and breccia. The dacite is characterized by columnar joints, in diameter, and exhibiting locally radiating patterns. This volcanic centre formed in a subglacial to englacial environment between 130,000 and 90,000 years ago, as shown by the existence of distinctive, radial columnar joint patterns, a glassy to fine-grained matrix and stratigraphic relationships to overlying glacial till.