The BGS Lexicon of Named Rock Units — Result Details

Dryden Flags Formation

Computer Code: DRY Preferred Map Code: DRY
Status Code: Pending Upgrade
Age range: Pragian Age (DP) — Pragian Age (DP)
Lithological Description: Brownish green shales and siltstones with a few sandstone bands; contains interbedded chert and rhyolitic to andesitic lava and ash at NJ 494 277, near Windyfield.
Definition of Lower Boundary: Change from dominantly arenaceous to dominantly argillaceous lithologies.
Definition of Upper Boundary: Removed by erosion.
Thickness: Approx. 260 metres in type section, but not seen; probably approx. 800 metres present in Castlehill (NJ 515 283) area.
Geographical Limits: Not defined.
Parent Unit: Rhynie Group (RHN)
Previous Name(s): Dryden Flags (-2768)
Dryden Shales [Obsolete Name And Code: Use DRY] (DRYS)
Dryden Formation (-873)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Dry Den, Sheet 76W, Scotland. 
Reference(s):
Wilson, J S G. 1890. Explanation of Sheet 76 Central Aberdeenshire. Memoir of the Geological Survey (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S076 S086