Abstract This sequence comprises the strata between the Woodbend Group (Chapter 8) and the Wabamun Group (Chapter 10). Stratigraphically it includes carbonates of the Nisku Formation and a succession of strata that comprise the "upper" Winterburn (Figure 2). This succession includes carbonates of the Blue Ridge Member of the Graminia Formation and fine siliciclastic sediments of the Calmar and Graminia "silt" intervals. Figure 1 depicts the basin configuration towards the end of Winterburn "time". It marks a major departure from the Woodbend configuration when a northeasterly opening to the basin existed between the Peace River Arch landmass and the Grosmont Platform Complex. Towards the end of Upper Nisku "time" a lobe of shale, along with coarser detrital sediment had blocked this entryway. This divided the Winterburn Basin into two geographic domains: firstly, a basin in central Alberta bordered by the "Meekwap" shelf to the north and northeast, the West Pembina shelf to the southeast and a less continuous shelf system in the Devonian "Deep Basin" to the west that presumably connected to an open seaway; and secondly, north and northwest of the Peace River Arch landmass, an early Winterburn basin that became infilled by shales of the upper part of the Fort Simpson Formation as far to the northwest as northeast British Columbia and contiguous areas of the Northwest Territories. Limestones of the Jean Marie Member of the Redknife Formation form a shelf bordering the open seaway to the west (Figure 1). The Winterburn Group consists of a lower transgressive phase and an upper regressive phase of deposition. In the lower transgressive phase shelfal carbonates of the Nisku Formation backstep away from the basin in central Alberta. During the upper regressive phase, carbonate platforms with varying amounts of evaporitic and terrigenous components, forestep into the basin.