The remaining quarter is composed of conglomeratic sandstones. Within this facies, fossilized bone occurs proximal to conglomeratic lenses. The Sycamore Canyon Member contains lenses of conglomerate, conglomeratic sandstone, and sandstone. First, the basal lower member consisting of purplish arkosic conglomeratic sandstone. It also contains beds of massive white, red or purple sandstone and conglomeratic sandstone. The Flatirons consist of conglomeratic sandstone of the Fountain Formation. The lower Oligocene is conglomeratic and pro-grades southward into evaporite and lacustrine deposits. These conglomeratic sandstone layers are interpreted as storm deposits. The coarsest facies are trough cross-bedded conglomeratic sandstone full of mineral concretions. They are cross-bedded, medium- to coarse-grained, and locally conglomeratic. The eastward sections comprise oolitic conglomeratic horizons of up to thick. In places the sandstone may be conglomeratic or ferruginous (rich in iron oxides). In turbidites, the basal part of a bed is typically coarse-grained and sometimes conglomeratic. The base of the layer contains thick-bedded, white conglomeratic sandstone. Tarkwa Mine mines several low-grade conglomeratic "reefs" of Tarkwaian type.