Sandy siltstone and fine-grained sandstones are interbedded with the aforementioned rock types. The Pico Member is mostly made of massive siltstones and sandstones interbedded with minor silty-sandstones. The dominant lithology of this unit is mudstone with some interbedded sandstones. They are interbedded with unfossiliferous sandstones and shales. They are often interbedded with limestones, shales, and fine-grained sandstones. The inner and midfan system contains interbedded thin to medium bedded sandstones and mudstones. The Burwash Basin consists of turbidites interbedded with felsic to indermediate volcanic tuff. It is typically interbedded with bioturbated mudstone. This member is a sandy siltstone that is interbedded with a fine-grained sandstone. The volcanics consist of underwater eruptions interbedded with sediment. Flysch typically consists of a sequence of shales rhythmically interbedded with thin, hard, graywacke-like sandstones. The basalts are interbedded with slate and greywacke, faulted, and intruded by granitic rocks. It consists of interbedded sands, clays and silts, with discontinuous clay lenses. The sands are interbedded with shales, and typically pinch-out updip. The Galeros Formation is a mainly greenish formation composed of interbedded sandstone, limestone, and shale.