Northern Ireland Chalk nomenclature (Ulster Cretaceous Province) - Ulster White Limestone Group: Post-Larry Bane Chalk Subgroup: Port Calliagh Chalk Formation
The Port Calliagh Chalk Member was first proposed in Fletcher (1977) and adopted in BGS publications subsequently. It is regarded as a formation herein.
Port Calliagh [D 112 420] inlet west of Castle Point near Ballycastle, north Antrim and to the east under Castle Point.
Primary Reference Section
Ballymagarry Quarry and around Ballycastle Harbour in the North Antrim Basin, in three quarries on the western Londonderry Shelf region, at Whiterock in Belfast and in Small and Hayes Quarry north-east of Lurgan.
None but informally divided into units A to F from the base.
Limestone (chalk) with numerous flint bands displaying large, tabular and complex habit.
Definition of upper boundary
Conformable at a prominent weathered-out bedding plane at the top of ‘Bed’ F with the Ballycastle Chalk Formation,
Definition of lower boundary
Conformable on the Tanderagee Chalk Formation at the lowest ‘separation plane’ immediately beneath the ‘belt of complex flints’ seen in the Ballycastle section.
12.40m at the type-site.
Outcrops in the Southern Uplands area (in isolated areas), the North Antrim Basin and in the southern part of the Londonderry Shelf. Absent in the East Antrim Basin, the Highland Border High and northern Londonderry shelf due to pre-Palaeogene erosion.
Port Calliagh Chalk Member.
Forms the lower part of the Ballycastle White Limestone (Wood, 1967).
Ulster White Limestone Group.
Age and biostratigraphy
Upper Cretaceous, Maastrichtian. Belemnella lanceolata Zone.
Fletcher (1967, 1977).