The Canning Basin is a large intra-cratonic basin which underlies an onshore area of 430,000sq. km. The study area, located on the Barbwire Terrace, contains a series of stratigraphic boreholes drilled by Western Mining Corporation Ltd., which provide fully cored sections through the previously poorly exposed Grant Group. From this core, integrated with seismic data and wireline logs, the Grant Group has been divided into three new formations, each containing a number of distinctive and intimately related facies types. The basal Hoya Formation comprises a complex suite of interbedded diamictites, sandstones and mudstones. The diamictites are interpreted as lodgement tills, melt-out tills and flow tills, deposited from the retreating ice sheet. Interbedded with the diamictites are massive and laminated mudstones, deposited under fluctuating marine and lacustrine conditions. Stacked cross-bedded sandstone units are restricted to the west of the study area, forming subsurface linear mounded features, clearly displayed on the regional seismic. These sandstones are interpreted to be deposited from braided fluvial outwash systems. However, the majority of sandstones are massive and normally graded, of mass-flow origin, deposited from a series of subaqueous fans fed by meltwater from the ice sheet. The overlying Calytrix Formation contains a thin basal sandstone unit, rich in marine fauna, but is characterised by a thick sequence of basinal mudstones. It is overlain by the Clianthus Formation, which has a basal fluvial sandstone unit, capped by heterolithic sandstones, siltstones and mudstones, interpreted to be shallow marine shelf deposits. The Grant Group sediments record the gradual deglaciation of the basin, and indicate that the ice sheet was extensive during the Perm- Carboniferous. The Hoya Formation contains all the glaciogenic sediments, and provides evidence for periodic ice advance and retreat. The mudrock dominated Calytrix Formation is interpreted to reflect the rise in sea level subsequent to the main deglaciation phase, and the regressive package of sediments that form the Clianthus Formation result from isostatic uplift and basin fill under post glacial conditions.