10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 53 



Derivation. — From Notch Peak, the type locaHty. 



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 Hmestones, 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. — INIiddle Cambrian fauna. 



Wheeler Formation 



Type Locality. — Center of Wheeler Amphitheater, southeast of 

 Antelope Springs, House Range, Utah. 



Derivation. — From Wheeler Amphitheater, the type locality. 



