The coastal bluffs have verticality as steep as 60 percent, while some of the quarry surfaces are completely sheer. The limestone beds within the quarry are hard and fresh, with close- and widely spaced fractures. Some of these beds are underlain by greenstone, an altered volcanic rock that becomes less weathered with depth. The eastern portion of the quarry area is underlain by alluvial terrace deposits. The beach littoral zone is underlain by Holocene age beach sand and the upper sands vary in depth by season, depending on the surf scouring of beach sands in the winter and the gradual rebuilding of sands in the summer.