Type Locality:

Briggs Turkey Lake No. 1, 61 deg 07'30"N, 120 deg 22'30"W, 237.7-829.1 m (780-2,720 ft).

Distribution:

Thickness ranges from 480 m (1,430 ft) over the Tathlina arch to over 1,000 m (3,050 ft) in the Mackenzie Plain. Widely distributed in northwestern Alberta, in the southwestern N.W.T. to 64 deg N, and in British Columbia north of Peace River arch.

Lithology:

Greenish-grey to grey shale and mudstone, variably calcareous, silty or sandy.

Relationship:

In the type well the Fort Simpson is overlain by the Jean Marie Member (Redknife Fm) and underlain by the Horn River Fm. Southwest from the type well it has become common practice to place the top of the formation at the base of the lowest mappable Upper Devonian limestone unit, thus the top of the formation shifts up section from east to west, from the base of the Jean Marie Member to the base of the Kakisa, Trout River or Tetcho formations (eg. Torrie, 1973). Farther west, equivalent strata are part of the Besa River Fm. Northwest from the type well the formation has been mapped as far as 64 deg N (Douglas and D.K. Norris, 1961, 1974); equivalent strata further north are part of the top of the Imperial Fm. Southeast from the type well the base of the formation was redefined as the top of the Muskwa Fm (G.K. Williams, 1977a). Equivalent strata to the southeast include the Tathlina, Twin Falls and Hay River formations or, in Alberta most of the Woodbend Group.

Other Citations:

Bassett and Stout, 1967; Belyea and McLaren, 1962; A.E. Cameron, 1918; Douglas and D.K. Norris, 1961, 1974; Fuller and Pollock, 1972; Torrie, 1973; G.K. Williams, 1977a.