Ellis Group
Stratigraphic range: Bajocian-Oxfordian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological group
Sub-units	Swift, Rierdon, Piper & Sawtooth Formations
Underlies	Mannville Group
Overlies	Rundle Group & Shaunavon Formation
Thickness	up to 150 m (490 ft)^[1]
Lithology
Primary	Shale, sandstone
Other	Siltstone, limestone
Location
Coordinates	48°00′N 108°36′W / 48.0°N 108.6°W / 48.0; -108.6
Approximate paleocoordinates	40°54′N 49°12′W / 40.9°N 49.2°W / 40.9; -49.2
Region	Alberta, Saskatchewan Montana, Wyoming
Country	Canada United States
Extent	WCSB
Type section
Named for	Fort Ellis
Named by	A.C. Peale
Year defined	1893
Ellis Group (Canada)

The Ellis Group is a stratigraphical unit of Bajocian-Oxfordian age in Alberta, Saskatchewan, Montana and Wyoming in the Western Canadian Sedimentary Basin. It takes the name from Fort Ellis, Montana, and was first described in outcrop in the Rocky Creek Canyon by A.C. Peale in 1893.^[2]

Lithology

The Ellis Group is composed of shale and sandstones deposited in a marine and transitional environment. ^[1]

Hydrocarbon production

Oil is produced from the Sawtooth Formation in southeastern Alberta.

Distribution

The Ellis Group laterally occurs in the subsurface in southern Alberta and northern and central Montana.^[1] It is typically 80 metres (260 ft), but thickens on either side of the Sweetgrass Arch and reaches up to 150 metres (490 ft) in southeastern Alberta.

Subdivisions

The Ellis Group includes the following formations, from top to bottom:

Sub-unit	Age	Lithology	Max. Thickness	Notes
Swift Formation	Oxfordian	marine shale, transitional shale, siltstone and sandstone	41 m (130 ft)	^[3]
Rierdon Formation	Bathonian to Callovian	marine shale and limestone	60 m (200 ft)	^[4]
Sawtooth Formation	Bajocian to Bathonian	quartzose sandstone with shale	41 m (130 ft)	^[5]
Piper Formation	Middle Jurassic	sandy limestone (top) papery shale siltstone and shale grey limestone white gypsum (base)	23 m (80 ft)	^[6]

Relationship to other units

The Ellis Group is unconformably overlain by the shales and sandstones of the Mannville Group and rests on the carbonates of the Rundle Group. It grades westwards to the shales of the Fernie Group, and eastwards to the shale, sandstones and limestones of the Vanguard and Shaunavon Formations.^[1]

References

^ ^a ^b ^c ^d Lexicon of Canadian Geologic Units. "Ellis Group". Archived from the original on 2013-02-21. Retrieved 2010-01-01.
^ Peale, A.C., 1893. The Paleozoic section in the vicinity of Three Forks, Montana. United States Geological Survey, Bulletin 110, p.9-56.
^ Lexicon of Canadian Geologic Units. "Swift Formation". Archived from the original on 2012-07-09. Retrieved 2010-01-03.
^ Lexicon of Canadian Geologic Units. "Rierdon Formation". Archived from the original on 2012-07-07. Retrieved 2010-01-03.
^ Lexicon of Canadian Geologic Units. "Sawtooth Formation". Archived from the original on 2012-07-07. Retrieved 2010-01-03.
^ Lexicon of Canadian Geologic Units. "Piper Formation". Archived from the original on 2012-07-08. Retrieved 2010-01-03.

v t e Western Canadian Sedimentary Basin
Hydrocarbon history	Oil sands and heavy oil Frontier exploration and development Natural gas liquids Natural gas
Depositional regions	Southern Alberta Central Alberta Northwestern Alberta Plains South-central Canadian Rockies foothills North-east Plains North-central foothills Liard River Fort Nelson Northern Rocky Mountains Fort St. John Saskatchewan Western Manitoba
Southern Alberta plains	Cypress Hills FM Porcupine Hills FM Ravenscrag FM Edmonton GRP Belly River GRP Oldman FM Foremost FM Pakowki FM Milk River FM Colorado GRP Mannville GRP Ellis GRP Swift FM Rierdon FM Sawtooth FM Rundle GRP Banff FM Exshaw FM Bakken FM Wabamun FM Crowfoot FM Nisku FM Ireton FM Leduc FM Cooking Lake FM Beaverhill Lake GRP Elk Point GRP Canadian Shield
Saskatchewan	Cypress Hills FM Ravenscrag FM Frenchman FM Whitemud FM Eastend FM Bearpaw FM Judith River GRP Belly River FM Oldman FM Foremost FM Lea Park FM Pakowki FM Milk River FM Colorado GRP Viking FM Mannville GRP Pense FM Cantuar FM Success FM Vanguard FM Ellis GRP Swift FM Rierdon FM Sawtooth FM Shaunavon FM Piper FM Gravelbourg FM Gypsum Springs FM Watrous FM Big Snowy GRP Madison GRP Charles FM Poplar Ratcliffe Midale Mission Canyon FM Kisbey SS Alida Tilston Lodgepole FM Souris Valley Three Forks GRP Bakken FM Big Valley FM Torquay FM Saskatchewan GRP Birdbear FM Duperow FM Manitoba GRP Souris River FM Elk Point GRP Davson Bay FM Prairie FM Winnipegosis FM Ashern FM Interlake FM Stonewall FM Stony Mountain FM Herald FM Yeoman FM Winnipeg FM Deadwood FM Canadian Shield