Palynomorph assemblages are reported from the Kotick Point and Whisky Bay formations in west and north-west James Ross Island, Antarctic Peninsula. The microfloras, particularly the dinoflagellate cyst florules, indicate an Aptian to early/mid Albian age for the Kotick Point Formation and a mid Albian to Turonian age for the Whisky Bay Formation on the basis of comparison with records from other Southern Hemisphere localities. The ages adduced broadly corroborate those previously derived from macrofaunas. The dinoflagellate cyst floras are closely comparable with those previously reported from Australasia to the extent that recognition of certain microplankton zones is possible. The miospore flora is largely composed of long ranging taxa of limited age diagnostic value. The palynoflora comprises 77 dinoflagellate cyst, 52 miospore and 7 acritarch, chlorophyte and prasinophyte taxa.

The Pedersen Formation includes conglomerate-dominated successions exposed on Pedersen Nunatak (142 m thick) and southern Sobral Peninsula (750–1000 m thick). As re-defined here, it also includes mudstone and sandstone in tectonic contact with Nordenskjöld Formation strata on a nunatak north of the Sobral Peninsula conglomerate outcrops. 40Ar/39Ar ages and palynological data indicate an early Aptian age for the lower part of the formation on Sobral Peninsula. The Pedersen Nunatak strata have yielded conflicting age determinations, although an Early Cretaceous age seems likely. The Sobral Peninsula conglomerates are lithologically similar to, and possibly coeval with, basal Gustav Group strata (Lagrelius Point Formation) on James Ross Island. Although further field sampling is required to resolve the age of the Pedersen Nunatak strata, on present evidence the Pedersen Formation appears to form part of the same tectono-stratigraphic unit as the lower part of the Gustav Group, and we therefore propose that it be included in that group.