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The area comprises two distinct physiographic regions, the Cumberland-Pictou Lowlands and the Cobequid Highlands. Bedrock, till, glaciojluvial, glaciomarine, alluvial, colluvial, marine, and organic sediments make up the sUJface materials. Large areas of mechanically and chemically weathered bedrock, residuum, on the Cobequid Highlands are believed to derive from a pre-Wisconsinan nonglacial interval. The first glacier flow recorded in the area, thought to be Early Wisconsinan in age, was eastward across Chignecto Bay, then southeastward. It formed the compact, calcareous M cCarron Brook Till. After this event there is some evidence for a brief nonglacial interval. Ice then.flowed southward and southwestwardfrom a centre over Prince Edward Island. The grey Joggins Till and the reddish-brown Eatonville Till were formed during this flow. The next glacial event was a pulse of southwestward.flow which created the bouldery Shu lie Lake Till and a moraine which blocks Parrsboro Gap. The Shu lie Lake Till terminates along an east to west line north of the Cobequid Highlands marked by Shulie and Welton lakes. This till limit represents a glacier marginal stand. These successive till-forming ice flows are termed the McCarron Brook, Eatonville and Shulie Lake phases. De glaciation probably occurred at the end of the Eatonville Phase about 14 000 years B .P. as glaciomarine deltas were being constructed along the north shore of Minas Basin. Meltwater was cut off to the deltas during Shulie Lake Phase when the moraine across Parrsboro Gap was constructed. Radiocarbon dates and pollen evidence from buried peat and basal organic sediments north of Shulie Lake Till limit suggest that ice persisted there until 12 000 BP and perhaps as recently as JO 500 BP. Marine limit decreases from 37 m above m.s.l. to 15 m northeastward along Chignecto Bay. Marine limit also decreases eastward in Minas Basin from 38 mat West Advocate to 22 mat Parrsboro. The decrease in marine limit along the.flow path of the Shulie Lake Phase suggests that the formation of raised marine features on the south coast of Chignecto Bay was delayed by ice in the bay. Pb and Zn geochemical anomalies in the locally-derived Shulie Lake Till suggest the presence of this type of mineralization in the Late Carboniferous Cumberland Group in the map area. Organic-rich channel-lagfacies may have been the focus for Pb-Zn precipitation within the Cumberland Group sandstones. Cu and As anomalies in residuum developed from the Devono-Carbon!ferous Greville River Formation correlate with chalcopyritearsenopyrite mineral occurrences along Glooscap Fault.

Three atomic mass spectrometry (AMS) dates have been obtained for shell material from the bottomset beds of a glaciomarine delta at Spencers Island, Nova Scotia, near the head of the Bay of Fundy. The sediments in the delta are part of the previously undated Five Islands Formation, and are the first direct indictaion of the age of deglaciation in this region. The dates range from 14,300 to 12,600 yr B.P. and record the duration of deposition of a diamicton under the deltaic deposits and of the delta itself. The diamicton may have formed around 14,000 yr B.P. under ice-shelf or calving-bay conditions, or by a readvance of grounded ice. The Spencers Island delta is part of a prominent ice-marginal stand marked by numerous deltas along the Minas Basin. The time of formation of the deltas and the inferred ice margin is between 13,500 and 12,000 yr B.P. based on the Spencers Island dates and palynologically confirmed dates on the base of lake-sediment cores from the delta surface. Ice-marginal glaciomarine deposits near St. John, New Brunswick, record a range of radiocarbon dates similar to the Spencers Island dates. This implies that the Bay of Fundy became virtually ice free about 14,000 yr B.P.

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