Source: SILTS newletter 2003
A thick accumulation of sand and gravel that was deposited in front of advancing glaciers during the early stages of the Fraser Glaciation.
1. "Quadra Sand is a late Pleistocene lithostratigraphic unit [i.e. a type of rock grouping] with widespread distribution in the Georgia Depression, BC and the Puget Lowland.
It consists mainly of horizontally, cross-stratified, well sorted sand that is overlain by till deposited during the Fraser Glaciation and underlain by fluvial and marine sediments deposited during the preceding nonglacial interval. … it is older than 29,000 radiocarbon years at the north end of the Strait of Georgia, but is younger than 15,000 years at the south end of Puget Sound.
(Source: Quadra Sand and its relation to the late Wisconsin glaciation of southwest British Columbia, Canadian Journal of Earth Sciences, 1976, 13(6): 803-815, 10.1139/e76-083)