A major regressive event. Low reservoir permeability (generally less than 1 md) and porosity (1 to 10%) are interpreted to be the result of early compaction, cementation, and diagenesis. The lower part is a 1,300 ft (400 m) thick sand-rich deep-sea fan complex, which overlies basin plain turbidite deposits of the Juncal Formation. The upper Matilija Sandstone consists of shallow-marine cross-bedded sandstone, red beds, and carbonate-evaporite-lignite sequences which overlie the turbidites. Deposition of the Matilija Sandstone was terminated by a rapid basin deepening event which culminated in deposition of basin plain, slope, and turbidite deposits of the Cozy Dell Formation. The only remaining porosity is secondary.--Modified journal abstract.