Derivation.—From Notch Peak, the type locality.
Character.—Gray, arenaceous limestone in more or less massive layers.
Thickness.—1,890 feet.
Organic Remains.—Upper Cambrian fossils occur in the lower portion, and the formation extends in its upper portion to the Lower Ordovician.
Orr Formation
Type Locality.—Orr Ridge, a spur extending eastward from the main mass of Notch Peak, on the south side of Weeks Canyon, House Range, Utah.
Derivation.—From Orr Ridge, the type locality.
Character.—Gray, slightly arenaceous limestones and shales.
Thickness.—1,825 feet.
Organic Remains.—Upper Cambrian fossils; in its lower part the formation extends to the shales of the Weeks formation, which carry Middle Cambrian fossils.
Weeks Formation
Type Locality.—North side of Weeks Canyon, north of Orr Ridge, House Range, Utah.
Derivation.—From Weeks Canyon, the type locality.
Character.—Thin-bedded shaly limestones, with a few bands of oolitic and arenaceous limestones.
Thickness.—1,390 feet.
Organic Remains.—Middle Cambrian fauna.
Marjum Formation
Type Locality.—Cliffs on the south side of Marjum Pass, House Range, Utah.
Derivation.—From Marjum Pass, the type locality.
Character.—Gray to dark, more or less thin-bedded, arenaceous limestone.
Thickness.—1,092 feet.
Organic Remains.—Middle Cambrian fauna.
Wheeler Formation
Type Locality.—Center of Wheeler Amphitheater, southeast of Antelope Springs, House Range, Utah.
Derivation.—From Wheeler Amphitheater, the type locality.
