Scotland Chalk nomenclature (Scottish Chalk Province) - Inner Hebrides Group: Feorlin Sandstone Formation

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Name

The Feorlin Sandstone Formation was formally proposed by Braley (1990) as part of the Beinn Iadain Mudstone Formation but is considered as a formation in its own right beneath the Beinn Iadain Mudstone Formation and questionably beneath the Clach Alasdair Conglomerate Member by Mortimore et al. (2001).

Type section

Feorlin Cottage [NM 5317 2225] at Carsaig, Mull.

Primary Reference Section

Caisteal Sloc nam Ban [NM 431 312] in the Wilderness on Mull.

Formal subdivision

None

Lithology

Slightly glauconitic sandstone with silicified chalk pebbles.

Definition of upper boundary

Conformable with the rest of the Ben Iadain Mudstone Formation (Braley, 1990) or questionably beneath the Clach Alasdair Conglomerate Member (Mortimore, Wood and Gallois, 2001).

Definition of lower boundary

Unconformable on the Strathaird Limestone Formation when considered as the basal member of the Ben Iadain Mudstone Formation (Braley, 1990), or on the Gribun Chalk Formation or Morvern Greensand (Mortimore, Wood and Gallois, 2001) as a formation in its own right.

Thickness

c. 8.5 m attributed to these beds at Caisteal Sloc nam Ban in the Wilderness on Mull.

Distribution

Known from the island of Mull.

Previous names

None

Parent

Inner Hebrides Group.

Age and biostratigraphy

Upper Cretaceous or Paleocene.

References

Braley (1990); Lowden, Braley, Hurst and Lewis (1992); Mortimore, Wood and Gallois (2001). (In this volume a number of the correlations in the earlier works are adjusted and the dating of the sequence refined. The name is given Formational status in the successions on Mull).

NOTE: - The Feorlin Sandstone Formation of Mortimore, Wood and Gallois (2001) is considered to be a formation in its own right and forming part of the Upper Cretaceous sequence (or possibly Paleocene). At the Caisteal Sloc nam Ban section on the Isle of Mull the formation is shown beneath the Clach Alasdair Conglomerate Member (which elsewhere in Mortimore et al. (2001) is shown as Santonian to Maastrichtian in age) itself within the Strathaird Limestone Formation. Braley (1990) considers the unit to be a member within the Ben Iadain Mudstone Formation of Paleocene or younger age.