Erik Nielsen

During the summer of 1969, field work was carried out for a period of five weeks along the coastal peninsula that separates Hudson Bay from Richmond Gulf. The peninsula is a cuesta sloping approximately 10· to the west, and is composed of arkoses, dolomites, and limestones, capped by basalt.

Flights of beaches ascend both the dip and scarp slopes. On the latter they are confined to large protected east trending valleys. After deglaciation when the relative sea-level was high, the cuesta formed a series of islands. The beaches formed between islands.

The upper marine limit is measured at 860 ft. a.m.s.l. on the southern part of the cuesta and 765 ft. On the northern part. The upper marine limit was easily recognized in the field by the sharp contact between boulder beaches and ablation (ground) moraine which is preserved above the upper marine limit. The upper marine limit may also be detected on air photographs by the abundance of small lakes on the basalt above the upper marine limit.

Marine shells, pelecypods and barnacles, were collected for rediocarbon dating, the highest at 565 ft. Shells were not found in the very high boulder beaches, but were restricted to lower levels where the sediment is composed of stratified sands or marine clay. The nature of the sediment can easily be distinguished on the air photographs.

Ventifacts were discovered which may or may not have been formed by winds blowing off the retreating ice cap in central Labrador-Ungava during the late Pleistocene.

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