Distribution:

Its thickness is about 48-53 m (Williams and Telford, 1986), but increases to the east, and decreases to the west onto the Precambrian Shield (Wilson, 1964) (Hamblin, 1998).

Lithology:

A lower member of interbedded sandstone and shale and an upper member of interbedded sandstone, shale, limestone and silty dolostone are evident in outcrop (Williams and Telford, 1986). Wilson (1964) states that a thin basal conglomerate is locally present and implies that shale is the dominant lithology. Sandstones are light grey to greenish, thin to thck bedded, calcareous to noncalcareous and fine grained with minor coarse beds (Williams and Telford, 1986). Crossbedding, ripples, desiccation cracks, flutes and burrows are common (Williams and Telford, 1986). Shales are dark grey to green to maroon limestones, common in the upper member, are either shaley and fine-crystalline in western areas, or medium crystalline with stylolites and crossbeds in eastern areas (Williams and Telford, 1986). Minor silty dolostones are grey, fine crystalline and display prominent conchoidal fracture (Hamblin, 1998).

Relationship:

The lower contact is likely a disconformity sharply overlying the Lower Ordovician Oxford Formation (Wilson, 1964), and the top is a disconformity placed at the upper limit of thick shale interbeds overlain by the Middle Ordovician Shadow Lake sandstones (Williams and Telford, 1986). It is unclear whether this unit should be considered as the latest portion of the Sauk Sequence (Sloss, 1963) or as the earliest manifestation of the Tippecanoe Sequence (Sloss, 1963) (Hamblin, 1998).

History:

The term Rockcliffe Formation was first proposed by Wilson (1937) for the Lower-Middle Ordovician interbedded sandstone and shale well-exposed in the Rockcliffe Park area of Ottawa (Williams and Telford, 1986) (Hamblin, 1998).

References:

Hamblin, A.P., 1998. Upper Cambrian and Lower (Middle?) Ordovician sandstones of the Ottawa Embayment: summary of literature; Geological Survey of Canada, Open File 3670, 10 pages.

Sloss, L.L., 1963. Sequences in the cratonic interior of North America. Geological Society of America Bulletin, v. 74, p. 93-114.

Williams, D.A. and Telford, P.G. 1986. Paleozoic geology of the Ottawa area; Geological association of Canada, Mineralogical Association of Canada, Canadian Geophysical Union Joint Annual Meeting, Field trip Guidebook 8, 25 p.

Wilson, A.E., 1937. Erosional intervals indicated by contacts in the vicinity of Ottawa, Ontario, Transactions of the Royal Society of Canada, Vol. 31, pages 45-60

Wilson, A.E., 1964. Geology of the Ottawa-St. Lawrence Lowland, Ontario and Quebec. Geological Survey of Canada, Memoir 241, 66 p.