West comprises only one lava flow that reaches a thickness of . To the northwest, Mount Cayley constitutes the largest and most persistent volcano in the central Garibaldi Belt. It is a highly eroded stratovolcano composed of dacite and rhyodacite lava that was deposited during three phases of volcanic activity. The first eruptive phase started about four million years ago with the eruption of dacite lava flows and pyroclastic rock. This resulted in the creation of Mount Cayley itself. Subsequent volcanism during this volcanic phase constructed a significant lava dome. This acts like a volcanic plug and composes the lava spines that currently form pinnacles on Cayley's rugged summit. After Mount Cayley was constructed, lava flows, tephra and welded dacite rubble were erupted. This second phase of activity million years ago resulted in the creation of the Vulcan's Thumb, a craggy volcanic ridge on the southern flank of Mount Cayley. Lengthy dissection from an extended period of erosion demolished much of the original stratovolcano. Volcanic activity after this prolonged period of erosion produced thick dacite lava flows from parasitic vents 300,000 years ago that extended into the Turbid and Shovelnose Creek valleys near the Squamish River. This subsequently created two minor parasitic lava domes 200,000 years ago. These three volcanic events are in contrast to several others around Cayley in that they do not show signs of interaction with glacial ice. Pali Dome, an eroded volcano north of Mount Cayley, consists of two geological units. Pail Dome East is composed of a mass of andesite lava flows and small amounts of pyroclastic material. It lies on the eastern portion of the large glacial icefield that covers much of the Mount Cayley volcanic field. Much of the lava flows form gentle topography at high elevations but terminate in finely jointed vertical cliffs at low elevations. The first volcanic activity likely occurred about 25,000 years ago, but it could also be significantly older. The most recent volcanic activity produced a series of lava flows that were erupted when the vent area was not covered by glacial ice. However, the flows show evidence of interaction with glacial ice in their lower units. This indicates that the lavas were erupted about 10,000 years ago during the waning stages of the Fraser Glaciation. The ice-marginal lava flows reach thicknesses of up to . Pali Dome West consists of at least three andesite lava flows and