Allenby Formation

Allenby Formation
Stratigraphic range: Ypresian 52.5–48 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Alternating Princeton Chert and coal sequences
Type	Geological formation
Unit of	Princeton Group, Eocene Okanagan Highlands
Sub-units	Princeton Chert, Vermillion Bluffs Shale
Overlies	Cedar Formation
Area	300 km2 (120 sq mi)[1]
Thickness	1,860–2,100 m (6,100–6,890 ft)[1]
Lithology
Primary	Shale, sandstone
Other	Coal–breccia, coal–chert
Location
Coordinates	49°22.6′N 120°32.8′W / 49.3767°N 120.5467°W / 49.3767; -120.5467
Approximate paleocoordinates	53°06′N 107°30′W / 53.1°N 107.5°W / 53.1; -107.5
Region	British Columbia
Country	Canada
Extent	Princeton Basin & Tulameen basin
Type section
Named for	Allenby, British Columbia
Named by	Shaw
Year defined	1952
Allenby Formation (Canada) Show map of Canada Allenby Formation (British Columbia) Show map of British Columbia

The Allenby formation is a sedimentary rock formation in British Columbia which was deposited during the Ypresian stage of the Early Eocene. It consists of conglomerates, sandstones with interbedded shales and coal. The shales contain an abundance of insect, fish and plant fossils known from 1877 and onward, while the Princeton Chert was first indented in the 1950s and is known from anatomically preserved plants.

There are several notable fossil producing localities in the Princeton & Tulameen basins. Historical collection sites included Nine Mile Creek, Vermilian Bluffs, and Whipsaw Creek, while modern sites include One Mile Creek, Pleasant Valley, Thomas Ranch, and the Princeton Chert.