Type Locality: Cairnes (1907) described a generalized section on the Bow River near the mouth of Old Fort Creek, but as sections along the Bow are faulted or mostly inaccessible Stott (1963) designated atype section, originally described by Malloch (1911), on the more southerly of the two main branchesof Wapiabi Creek, in Twp. 41, Rge. 18W5M (52°37’30”N, 116°0’30”W), Alberta.

History: The term “Cardium Shales” was used by Dr. James Hector to identify beds from which fossil collections were made during the Palliser explorations (Whiteaves, 1895, p. 110). Cairnes (1907, p. 29)restricted the use of the term Cardium to the succession of sandstone within the shale series on Bow River. Rutherford (1927, p. 25) raised the unit to formation status.

Lithology: The Cardium Formation is characterized by its fine grained, marine sandstone. Six distinctive members are recognized in the central foothills (Stott, 1963). Three massive sandstone units are separated by marine and nonmarine shale. The basal sandstone is the Ram Member; the middle one, Cardinal, and the upper one, Sturrock. The lower shaly interval contains two members; the nonmarine Moosehound Member and the partly equivalent, partly overlying, marine Kiska Member.The shale between the Cardinal and Sturrock members is named the Leyland Member. In the subsurface of the Garrington-Caroline area, Alberta Walker (1983) proposed the names Raven River Member and Burnstick Member for two sandstone units within the lower part of the Cardium Formation. He also defined (1985) another sandstone within the Ricinus Field as the Ricinus Member. Krause (1984) divided the Cardium of the Pembina Field into the Pembina River and Cardium Zone members.

Thickness and Distribution: Extends from the Drywood River, near the International Boundary along the foothills into northeastern British Columbia near Dawson Creek (Stott, 1963, 1967). It extends fromthe front range eastward across the foothills belt into the plains. The formation is a major oil producerin the Pembina field southwest of Edmonton. The formation grades laterally eastward into shale. It ranges in thickness from a minimum of 22.6 m (74 ft) at Drywood River to a maximum of 108.8 m (357ft) at Ram River in the central foothills. Near Wapiti River in northeastern British Columbia the thickness is 41.8 m (137 ft).

Relationship to Other Units: The lower contact of the Cardium Formation is drawn at the base of thickly bedded sandstone lying on strata of the Blackstone Formation in the southern and central foothills, and of the approximately equivalent Kaskapau Formation in northeastern British Columbia. A transition zone from shale through interbedded shale and thinly bedded sandstone to massive sandstone is almost always present. The upper contact with the overlying Wapiabi Formation is sharp and well defined, but presumably conformable.

Paleontology: Ammonites comparable with Scaphites mariasensis Cobban and S. impendicostatusfrom the lower subzone of Scaphites preventricusus Zone occur in the upper beds of the Cardium Formation in the southern foothills. Wall and Germundson (1963) described the foraminiferal content.

Author: James Hector, as reported in Whiteaves, J.F. 1985; Cairnes, D.D., 1907.

Type Locality:Near Dunvegan, on the Peace River, northwestern Alberta.

Lithology:Consists of marine, non-marine and deltaic sandstone, light grey to yellowish buff in the type area. Beds may be massive, with cross-bedding. Thin beds of shale, shelly limestone and coal are present. The Dunvegan is dominantly marine in the area east of Dunvegan, but completely continental in northeastern British Columbia, where thick arkosic and conghmeratic beds are common. South of the Wapiti River in the foothills, and across the Grande Prairie area the sands are brackishwater to marine and usually porous.

Thickness and Distribution:Thickness is around 160 to 180 m (525 to 590 ft) in the Peace River area of Alberta, thinning to the south and east and disappearing; it is over 380 m (1246 ft) in the foothills ofthe Pine River. The Dunvegan extends from Fort Nelson and the liard River over the entire Peace River area and as far south as Wildhay River in the foothills.

Relationship to Other Units: The Dunvegan Formation is overlain conformably by the Kaskapau Formation in the Peace River area, except for an apparent hiatus near Watino, Alberta where the Dunveganoceras Zone seems to be missing. The contact is usually transitional, and where the basal unit of the Kaskapau becomes overly sandy the ternn Sakunka Member of the Dumvegan was suggested by Spieker (1921) for such beds in the Pine River area of British Columbia.

The Dunvegan is underlain conformably and transitionally by shales of the Fort St. John Group, whichare referred to as Sully and Cruiser formations in northeastern British Columbia and as the Shaftesbury Formation in the Peace River plains of Alberta.

The Dunvegan grades laterally to the east into the marine Labiche Formation and to the south into the middle part of the Sunkay Member of the Blackstone Formation . To the southeast in the plains the equivalent beds would be found in the lower Coloradc Group between the Second White Specks and the Fish scale marker bed. It coarsens northward to become the continental Fort Nelson conglomerate in northeastern British Columbia, which Stott (1968) included in the Dunvegan.

Paleontology:The Dunvegan carries a rich shallow water fauna in the type area and in the KakwaRiver area. It carries an extensive dicotyledon flora in northeastern British Coltimbia. Oysters, mussels,unionids and Inoceramus are common in Alberta, with I. rutherfordi indicating correlation with the Belle Fourche Shale of Wyoming. An arenaceous assemblage of Foraminifera dominated by Trochamminais found in brackish water tongues. The fossils indicate an Upper Cenomanian Age. The flora carriesPlatanus, Pseudocycas unjiga and numerous conifers and cycads, and ferns.

Author: Dawson, G.M.,1881

Type Locality: Home Regent “A” Swan Hills 10-10-67-10W5M, in Alberta, between 2489.3 and 2590.8m (8167 and 8500 ft). The name is derived from the Swan Hills, which rise above a relatively flat muskeg-plain area north of Whitecourt, Alberta.

History: In 1959-60 Fong introduced the term Swan Hills as a member of the Beaverhill Lake Formation for the oil-producing carbonate at Swan Hills and divided it into a lower dark brown member and an overlying light brown member. Leavitt and Fischbuch (1968) raised Fong’s Swan Hills Memberto formational status and included it, along with the Fort Vermilion Formation and the Waterways Formation in the Beaverhill Lake Group. Later Fischbuch (1968) divided the Swan Hills Formation into nine informal units designated from bottom to top as Divisions I to IX, and suggested that the Middle to Upper Devonian boundary occurs between Divisions V and Vl.

Lithology: The reef complexes constituting the Swan Hills Formation consist essentially of two contrasting rock types: a lagoonal series of facies consisting of dense, micritic, pelletoidal limestoneswith only minor skeletal material; and a reef to fore-reef series of facies consisting of coarse grained,commonly porous, bioclastic, organically constituted limestones. The Swan Hills Formation generally is a limestone unit, although some reef complexes are dolomitized.

Thickness and Distribution: In the general Swan Hills area Divisions I to III form a reef-rimmed platform on which isolated reef complexes of Division IV to IX are situated and the formation ranges fronds over152 m (500 ft) to less than 15 m (50 ft) in thickness. The formation extends southward and westwardand thins into the outcrop area, where it is known as the Flume Formation. Divisions I to III of the Swan Hills Formation extend northward from the type area around the Peace River Arch, across northern Alberta into the Northwest Territories and northeastern British Columbia, where they are known as the Slave Point Formation. These Slave Point-lower Swan Hills carbonates terminate at the margin of the Sulphur Point-Keg River facies front in northeastern British Columbia and the Northwest Territories.

Relationship to Other Units: The Swan Hills Formation is underlain conformably by evaporites of the Fort Vermilion Formation and, southwest of the Swan Hills area by clastics of the upper Elk PointGroup. The Swan Hills reef complexes are overlain and surrounded by nodular shale and micrites ofthe Waterways Formation. To the south the upper part of the Swan Hills Formation is correlative with the Flume Formation of the Rocky Mountain outcrop, and to the north the lower part of the Swan Hills Formation (Divisions I to lilt is correlative with the Slave Point Formation.)

Paleontology: The reefal facies of the Swan Hills Formation are populated mainly by sub-spherical,dendroid, bulbous and tabular stromatoporoids, with minor occurrences of crinoids, brachiopods,gastropods, ostracods and algae. The lagoonal facies contain quantitatively far less fossils, primarily of the stromatoporoid genus Amphipora.

Author: Fong, G., 1959, p. 95-108;1960, p. 195-209.

Type Locality: Type well B.A. Pyrcz No. 1, in 12-25-50-26W4M, in central Alberta, between 1544 and 1624 m (5065 and 5327 ft) partially cored. This ‘on-reef’’ section includes only the upper Ireton, and a more representative “off-reef” section is present in Imperial Labyrinth Lake 15-14-48-23W4M, between 1558 and 1684 m (5110 and 5525 ft), continuously cored.

History: Named after the railway siding of Ireton at the south end of the Leduc-Woodbend field. Originally proposed as a member of the then Woodbend Formation. Elevation of this formation to group status, proposed by Andrichuk and Wonfor (1954, p. 2505), resulted in the Ireton attaining formational status.

Lithology: Divided into three informal divisions on the basis of lithology. The upper Ireton consists of interbedded, fossiliferous, calcareous grey-green shales and argillaceous limestones. Fossil materialis generally present in thin coquinas, and rare silt horizons may exhibit small scale cross-bedding. A number of discontinuity surfaces are present within the sequence, evidence of early lithification. This unit is extensively dolomitized and in places includes a 20 m (66 ft) thick dolomitic carbonate unit referred to as the Camrose Member. The middle Ireton is composed of slightly calcareous, fissile, grey-green shale, with occasional thin (25 cm, 10 in) beds of calcirudite which contain abundant skeletal material and lithoclasts. The lower Ireton is made up of massive, dense, nodular and banded limestones with minor calcareous shale partings, interbedded with grey-green, calcareous, fissile shale.

Broadly sigmoidal log marker surfaces present within the sequence reflect preserved depositional topography and cross the lithologic divisions outlined above. These three lithologic divisions represent deposition in platform, slope and basinal settings respectively.

Thickness and Distribution: Present throughout most of central Alberta, the Ireton ranges in thickness from less than 3 m (10 ft) “on-reef” to 250 m (820 ft) in basinal areas. The upper Ireton averages 15 to 20 m (49 to 66 ft), the middle Ireton 120 m (394 ft), and the lower Ireton 30 m (98 ft).

In the East Shale Basin the unit averages 150 m (492 ft), thickening westwards as the underlying Duvernay thins. In the West Shale Basin it thickens to over 250 m (820 ft). On the southern Alberta Woodbend shelf it is present as a thin development which may extend into Saskatchewan. To the northeast it is truncated in the subsurface by the pre-Cretaceous unconformity.

Relationship to Other Units: Conformably overlies the Duvernay Formation, the contact often being facies controlled, with Duvernay sediments being the deep water equivalent of slope and platform deposits of the Ireton. This thick shale development represents regressive infilling of basinal areas between Leduc carbonate buildups that proceeded from southeast to northwest. It is conformably overlain in the East Shale Basin by platform carbonates of the Nisku Formation, and Nisku or Winterburn shale equivalents in the West Shale Basin. Further northwards Ireton shales thin into lower portions of the lithologically similar Fort Simpson Shales.

Paleontology: Upper Ireton: diverse benthonic fauna of ostracods, crinoids, gastropods, bryozoa, corals and brachiopods (csp. spiriferids), along with a pelagic fauna of conodonts, tentaculitids and foraminifera. Bioturbation is common. Middle Ireton: sparse benthonic fauna present in debris lensesand thought to be shelf-derived. Bioturbation is abundant. Some scattered pelagic forms. Lower Ireton:scattered pelagic forms, with bioturbation generally absent.

Author: Geological Staff, Imperial Oil Ltd., 1950.

Type Locality: Husky Waseca #1, in Lsd. 6, Sec. 22, Twp. 49, Rge. 23W3M, Saskatchewan has a good development of Waseca sand.

History: The sand has never been formally described, but the term Waseca is commonly used in the Lloydminster area of Alberta and Saskatchewan.

Lithology: The Waseca Sand is a fine to medium grained sandstone with laterally variable composition. It ranges from a quartz arenite to a feldspathic litharenite. It is usually moderately wellsorted and moderately well rounded, but this varies within short distances.

Thickness and Distribution: The sand and associated silts and shales are about 25 m (80 ft) thick inthe Lloydminster area. The term Waseca is restricted to the area around Lloydminster, and south to about Twp. 35.

Relationship to Other Units: The Waseca Sand is locally disconformable above the Sparky sand and is usually found about 15 to 20 m (50 to 70 ft) below the top of the Mannville Group. The presence of a sub-Waseca disconformity and the locally marked difference in composition between the Waseca and Sparky sands suggest that the Waseca is the first sand of the Grand Rapids Formation. Putnam (1980) suggested that the entire upper Mannville section above the Sparky Sand should be called Waseca because of difficulties in correlating the individual sands on a regional basis.

Author: Husky Oil, 1949.

Type Locality: The type section is at the Northwest No. 1 well, in Lsd. 1, Sec. 18, Twp. So, Rge. 8W4M, Alberta, between 674 and 703.5 m (2211 and 2308 ft).

Lithology: The Dina consists chiefly of quartz sandstone, with interbedded siltstone and shale. Sandgrains are rounded, frosted and unconsolidated, with a general lack of dark minerals, except in the basal zones, where chert pebbles and granules are present.

Thickness and Distribution: The thickness is controlled by the underlying eroded Paleozoic surface and ranges from zero to 60 m (200 ft). it is present in the Lloydminster area and can be traced southward to about Twp. 30 along the Alberta-Saskatchewan border.

Relationship to Other Units: The Dina is the basal member of the Mannville Group. It underlies the Cummings Member, except where local channelling is present and no distinguishable separation can be made between the Cummings and Dina. It overlies the eroded Paleozoic surface or a detrital zone. The Dina is correlative with the McMurray and Ellerslie.

Author: Nauss, A.W., 1945.

Type Locality: Along the Athabasca River, between Pelican Rapids and 8 km (5 mi) downstream from Joli Fou Rapids. Joli Fou Section No. 1 is located about 5.5 km (3.4 mi) below Joli Fou Rapids, in NW/4 Sec. 22, or SW/4 Sec. 27, Twp. 81, Rge. 17W4M. Joli Fou Section No. 2 is in the north-central part of a series of exposures some 61 m (200 ft) east of the river in the west-central part of Sec. 33, Twp. 82,Rge. 17W4M. Joli Fou Section No. 3 is in an exposure about 8 km (5 mi) downstream from Joli Fou Rapids, on the east side of the valley in NW/4 Sec. 35, Twp 82, Rge 17W4M, some 42.7 m (140 ft)above the river.

History: Originally designated Pelican shale by McConnell (1892), which usage was continued byMcLearn (1917). The name was changed by Wickenden (1949) to avoid confusion with the overlying Pelican sandstone succession.

Lithology: Dark grey, noncalcareous shale, with minor interbedded fine and medium grained sandstone. The sandstone occurs as lenses, commonly a few millimetres thick and as graded layers up to several centimetres in thickness, composed of horizontal or very gently inclined laminae. Bioturbated, shaly sandstones form scarce layers several centimetres thick in the upper part of the unit the interbedded sandstone is quartzose and micaceous, while near the base glauconitic sandstoneand quartz arenite are common. Subordinate lithologies include bentonite, pelecypod coquinas,nodular phosphorite and concretionary layers of calcite, siderite and pyrite. In central Saskatchewan the unit consists of interbedded glauconitic sandstone and noncalcareous mudstone of the Spinney Hill Sandstone, overlain by northward thinning Joli Fou shales of much reduced thickness. The Joli Fou Formation includes, at its base the interbedded shady sandstone, siltstone and mudstone of the Cessford (Basal Colorado) Sand in south eastern Alberta.

Thickness and Distribution: The unit is about 33 5 m (110 ft) thick in the Athabasca River exposures, thinning to about 10.7 m (35 ft) to the south of the Lesser Slave Lake area and to about 16.8 m (55 ft) in the Redwater area. The Joli Fou Formation attains a thickness of about 61 m (200 ft) in south-central Saskatchewan. The sequence pinches out in the Rocky Mountain Foothills of southern Alberta, where it is replaced by the lowermost sandstones of the Bow Island Formation. The unit is of widespread distribution in the subsurface of the Western Canada sedimentary basin.

Relationship to Other Units: The Joli Fou Formation is the basal unit of the Colorado Group. In northeastern Alberta it rests on the Grand Rapids Formation of the Mannville Group and is overlain by the Pelican Formation in southern Alberta and southern Saskatchewan. Joli Fou shales rest disconformably on the Pense Formation and equivalent sandstones, marking the top of the Blairmore-Mannville-Swan River sequence, and are overlain by sandstones of the Bow Island-Viking succession. The Viking-Joli Fou contact is a disconformity in west-central Saskatchewan. Where the Viking Formation is absent in parts of southern Saskatchewan the Joli Fou and Big River formations form a sequence of undifferentiated lower Colorado shale. In central Saskatchewan the top of the Joli Fou Formation is defined by a sharp contact with the overlying Flotten Lake Sand. The Joli Fou Formation corresponds to the lower part of the lower Ashville succession (Skull Creek Member) in southern Manitoba and is equivalent to the Skull Creek Shale of north-central Montana and North Dakota. It is equivalent to the Taft Hill and Flood members of the Blackleaf Formation of northern Montana.

Author: Wickenden, R.T.D., 1949.

Type Locality: Northwest Mannville No. 1 well, in Lsd. 1, Sec 18, Twp. 50, Rge. 8W4M, Alberta, between 642.5 and 688.5 m (2108 and 2193 ft).

History: Named after the railway siding of Ireton at the south end of the Leduc-Woodbend field. Originally proposed as a member of the then Woodbend Formation. Elevation of this formation to group status, proposed by Andrichuk and Wonfor (1954, p. 2505), resulted in the Ireton attaining formational status.

Lithology: Nauss (1945) described the Cummings member as principally dark grey to black shale containing abundant pyrite and foraminifera. Beds of salt-and-pepper sandstone are common and a coal seam occurs near the base in the type section. To the south and east, and in the Lloydminster area the Cummings is a clean, bar-type sandstone and the term Cummings is more often used in relation to this sandstone than the shales described by Nauss.

Thickness and Distribution: Thickness varies from zero to 27.5 m (90 ft) in the type area and thins to the south. The member thickens to the north and is probably equivalent, in part to the Clearwater Shale, which is about 80 rn (275 it) thick on the Athabasca River. The Cummings Member can be differentiated from rocks above and below it by the presence of characteristic foraminifera in its shales. It can be correlated to the Ostracod Zone in central Alberta.

Author: Nauss, A.W., 1945.

Type Locality: Commonwealth Manitou No. 2, in 8-26-2-9WPM, southern Manitoba, between 359.7and 426.7 m (1180 and 1400 ft), and Neepawa Salt Company No. 2, in 9-33-14-15WPM, between 228.6 and 301.7 m (750 and 990 ft). Suggested reference section is Tudale Neepawa 5-29-14-14WPM, between 214.7 and 272.2 m (704.5 and 893 ft), completely cored.

History: The name was first used by Kirk (1930) in manuscript map, for gypsum bearing beds outcropping in the vicinity of the town of Amaranth, in southwestern Manitoba. Wickenden (1945)subsequently noted two subsurface type sections.

Lithology: The Amaranth consists of two members (Stott, 1955). The lower Amaranth consists of hard, massive, reddish brown dolomitic shale that becomes progressively more silty and sandy towards the base, in places grading to a sandstone. Sand grains are characteristically medium grained, wellrounded, Frosted and pitted, and anhydrite inclusions and fracture fillings are common towards the top. A basal carbonate breccia is present in places. The upper Amaranth consists of massive beds of finely crystalline, bluish white anhydrite with interbeds of greenish grey to brown shale and dolomite. Bluishwhite chert concretions occur at the top of the unit. In proximity to the outcrop belt the anhydrite passesto gypsum and is utilized as a commercial source of gypsum for Manitoba and Saskatchewan.

Thickness and Distribution: The lower Amaranth ranges in thickness from zero to 45.7 m (150 ft) in southwestern Manitoba, the thickness being controlled primarily by the paleotopography of the underlying Paleozoic erosion surface. It is locally absent on paleotopographic highs in the Wawanesa area (vicinity of Twp. 8, Rge. 18WPM), and in a large area north of Virden. The upper Amaranth attains a maximum thickness of 53.3 m (175 ft) and thins progressively to the north and east, pinching out in the vicinity of Twp. 26. Amaranth beds also occur as isolated outliers or erosional remnants in the areaof the Lake St. Martin crater structure and in the Winnipeg area. A major channel-fill type of deposit occurs southeast of Winnipeg, in the Dominion City area (vicinity of Twp. 3) where Amaranth strata extend up to 110 km (79 mi) east of the “normal” erosional limit. The name is applied only in the outcrop belt and subsurface of southwestern Manitoba.

Relationship to Other Units: The Amaranth rests with marked angular unconformity on Mississippian limestones in the extreme southwestern corner of Manitoba, and oversteps progressively older Paleozoic strata to the north and east, to rest directly on Precambrian basement in the major Pre-Mesozoic erosion channel in the Dominion City area (vicinity of Twps. 2 and 3, Rges. 6 to 10EPM). Locally, in the Lake St. Martin area (vicinity of Twp. 32, Rge. 8WPM) it unconformably overlies asequence of brecciated Precambrian and lower Paleozoic strata and igneous (melt?) rocks of approximate Permian age which comprise the St. Martin Complex.

The unit is overlain with slight disconformity by limestones of the Reston Formation. It is directly correlative and continuous with the Watrous Formation of Saskatchewan. The lower Amaranth is correlative with the upper part of the Spearfish Formation and the upper Amaranth with the basal partof the Piper Formation of northern North Dakota.

Author: Kirks S.R., 1930.

Type Locality: South-central Saskatchewan. Type well is the Tidewater Davidson Crown No. 1, in Lsd.13, Sec. 4, Twp. 27, Rge. 28W2M, between 755 and 837 m (2476 and 2744 ft).

Lithology: Comprises a lower and an upper member. The lower member is typified by red shales and mudstones, frequently variegated with green, and thinly and irregularly interbedded with patches and blebs of laminated anhydrite and anhydrite inclusions. Basal beds across southern Saskatchewan arecommonly marked by sandstones, conglomerates and, locally by brecciated cherty anhydrite, white,light grey and massive, interbedded with buff, earthy microcrystalline dolomite and grey shale; both are interrupted by veinlets of anhydrite. The upper member, a bed of massive anhydrite several metres thick laps over the lower units along the edge of the Watrous area of distribution.

Thickness and Distribution: Although defined as one formation, there is by usage a tendency to separate the lower argillaceous member from the anhydritic upper. Both units are distributed across southern Saskatchewan south of 52°N, from the Manitoba border westward to 109°W. The lower member infills irregularities on the sub Mesozoic erosional surface and thus varies abruptly in thickness by about 30 m (98 ft). Combined thickness (both units) range from 110 m (361 ft) along the border with North Dakota to zero at the erosional edge.

Relationship to Other Units: The Watrous Formation is synonymous with the Amaranth Formation of Manitoba (Stott, 1955). Because the lack of fossils uncertainty exists as to the age of the lower member. The outward and upward expansion of marine facies in the Jurassic suggests that the lower member of Watrous Formation represents the beginning of the Jurassic marine transgression. However, on the basis of regional correlation it appears to be a northward extension of the Triassic Spearfish Formation of North Dakota. The upper member is correlated with the lower part of the Jurassic Nesson Formation.

Author: Milner, R.L. and Thomas, G. E., 1954.

Type Locality: Spearfish, South Dakota, on the northern flank of the Black Hills of South Dakota and Wyoming.

Lithology: In the type region consists of red shale, siltstone and sandstone, with thick beds of gypsum near the base. Rests with sharp contact on the Permian Minnekahta Limestone and is overlain unconformably by the Jurassic Sundance Formation. In the subsurface of the Williston Basin of North Dakota the formation is divided into 3 members: the Belfield, Pine Salt and Saude.

Thickness and Distribution: The red-bed facies comprising this formation is continuous from Wyoming, where it is equated with the Chugwater Formation, northeast into the Williston Basin of North Dakota,Saskatchewan and Manitoba. However, only the upper portion may be present in Canada,represented by the lower members of the Watrous and Amaranth formations Thickness of the Spearfish ranges from more than 260 m (886 ft) in northeastern Wyoming to 225 m (738 ft) in North Dakota to less than 100 m (328 ft) in Saskatchewan and Manitoba.

Relationship to Other Units: Unconformably overlies beds ranging from the Middle Permian in Wyoming to Mississippian and Upper Devonian in Saskatchewan. The name Spearfish has not come into general usage in Canada.

Paleontology: The reefal facies of the Swan Hills Formation are populated mainly by sub-spherical,dendroid, bulbous and tabular stromatoporoids, with minor occurrences of crinoids, brachiopods,gastropods, ostracods and algae. The lagoonal facies contain quantitatively far less fossils, primarily of the stromatoporoid genus Amphipora.

Author: Darton, N.H., 1899.

Type Locality: No type section indicated, but the thickest section occurs in the general vicinity of Waskada, Manitoba (Twp. 2, Rge. 25WPM). One of the thickest sections reported by Stott is in the Souris Valley et al. McKague 27-2 well, in 2-27-1-27WPM, between 661.4 and 716.3 m (2170 and 2350 ft).

Lithology: The unit changes laterally and vertically within short distances. Shales predominate butvary in color: green, bentonitic shales are common, and grey to black, slightly carbonaceous shales also occur, as well as traces of red shale and ironstone. Thin beds and lenses of sandstone are common, and are while, fine to very fine grained, calcareous, and commonly pyritic and glauconitic.

Thickness and Distribution: The Waskada occurs as an erosional wedge-edge; it is a subsurface unitdefined for southwestern Manitoba and does not extend to outcrop. It is present as far north as the Virden area (vicinity of Twp. 12). Its maximum thickness in Manitoba is 57.9 m (190 ft); equivalent stratain North Dakota attain a maximum thickness of about 90 m (295 ft). Waskada beds locally show share changes in thickness due to deeply incised pre-Cretaceous channels that have locally eroded throughthe Waskada into the underlying Melita Formation. The depth of channels is as much as 76 m (249 ft).

Relationship to Other Units: The unit is underlain conformably by variegated shales of the Melita Formation, and is overlain with marked unconformity by coarse sands of the basal Cretaceous SwanRiver (Blairmore) Formation, except along its northern edge, where the Swan River strata pinch outand Waskada beds are directly overlain by grey shales of the Ashville Formation. It correlates with the upper Vanguard Masefield Shale) of Saskatchewan, and with the Swift and possibly the Morrison formations of North Dakota.

Paleontology: Ammonites comparable with Scaphites mariasensis Cobban and S. impendicostatusfrom the lower subzone of Scaphites preventricusus Zone occur in the upper beds of the CardiumFormation in the southern foothills. Wall and Germundson (1963) described the foraminiferal content.

Author: Stott, D.F., 1955.