Type Locality:

South of Waterford to approximately 2 km south of North Point, northwestern shore of Prince Edward Island (NTS 21 I/16).

Distribution:

Van de Poll (1989) estimated the thickness of the Egmont Bay Formation to be 250 m. The formation underlies the western and southwestern part of Prince Edward Island and outcrops along the coast, at Egmont Bay, Cape Egmont, between Miminegash and North Point, and between Campbellton and West Point. In the subsurface offshore, it has been recognized in the Island Development Hillsborough No.1 well (46°07'27.12" N, 63°05'12.12" W), Hillsborough Bay, south of Charlottetown.

Lithology:

The formation is the second, fining-upward, megacyclic sequence of the now abandoned Prince Edward Island Group (the Egmont Bay Formation is now considered part of the Pictou Group). At the base of the Egmont Bay is a coarse, locally pebbly wacke, changing to mudstone with interbeds of fine wacke at the top. Plant fossils are common and include Cordaites and Calamites (Dawson and Harrington, 1871). The fluvioclastic megacyclic sequence includes smaller scale fluvial cycles comprising floodplain, channel and levee-splay facies associations.

Relationship:

The basal, coarse pebbly sandstone of the Egmont Bay sharply but conformably overlies the mainly red mudstone of the Miminegash Formation. At the upper boundary, mudstone and fine- to medium-grained wacke of the Egmont Bay is conformably overlain by quartz pebble conglomerate with interbedded, coarse- to medium-grained wacke of the Kildare Capes Formation. The Egmont Bay Formation is one of five formations formerly included in the Prince Edward Island Group by van de Poll (1989). In ascending order the five formations are: the Miminegash, the Egmont Bay, the Kildare Capes, the Hillsborough River and the Orby Head formations. Ryan et al. (1991) formerly abandoned the name Prince Edward Island Group, considering it to be a junior synonym of the Pictou Group. Accordingly, the Egmont Bay Formation is now included in the Pictou Group.

History:

The age of the red beds in Prince Edward Island has generated considerable debate. Dawson (1848) believed they could be in part post-Carboniferous, possibly Triassic. This was based on the belief that the vertebrate Bathygnathus borealis, discovered in a well on the Island, was Triassic. However, Case (1905) and Huene (1905) both demonstrated that Bathygnathus was Permian. Subsequently, megaflora and palynomorph data have confirmed the Carboniferous-Permian age for the red beds, and the Stephanian age for the Egmont Bay Formation.

Other Citations:

Barss et al., 1963, 1979; Case, 1905; Darrah, 1936; Dawson and Harrington, 1871; Hacquebard, 1972; Howie, 1977; Huene, 1905; van de Poll 1989.

References:

Barss, M.S., Bujak, J.P., and Williams, G.L., 1979. Palynological zonation and correlation of sixty-seven wells, eastern Canada; Geological Survey of Canada, Paper 78-24, 118 p.

Barss, M.S., Hacquebard, P.A. and Howie, R.D. 1963. Palynology and stratigraphy of some Upper Pennsylvanian and Permian rocks of the Maritime Provinces. Geological Survey of Canada, paper 63-3, pages 1-13.

Case, E.E. 1905: Bathygnathus borealis Leidy, and the Permian of Prince Edward Island. Science, v. 22, pp. 52-53.

Darrah, W.C. 1936: Permian elements in the fossil flora of the Appalachian Province: H. Walchia. Harvard University Botanical Museum leaflets, no. 4, pp. 9-19.

Dawson, J.W. and Harrington, B.J. 1871: Report on the geological structure and mineral resources of Prince Edward Island. John Lovell, Montreal.

Hacquebard, P.A., 1972. The Carboniferous of eastern Canada; Septieme Congres International de Stratigraphie et de Geologie du Carbonifere, Krefeld 1971, Compte Rendu, vol. 1, pp. 69-90.

Howie, R.D. 1977: Geological studies and evaluation of MacDougall Core Well 1A, western Prince Edward Island. Geological Survey of Canada, Paper 77-20.

Huene, F. von. 1905: Pelycosaurier im Deutschen Muschelkalk. Neues Jahrbuch für Mineralogie, vol. 20, pp. 321-353.

Van de Poll, H.W. 1989. Lithostratigraphy of the Prince Edward Island redbeds; Atlantic Geology, vol.25, no.1, pp.23-35.