The BGS Lexicon of Named Rock Units — Result Details

Underbarrow Flag Formation

Computer Code: UND Preferred Map Code: Und
Status Code: Full
Age range: Ludfordian Age (SD) — Ludfordian Age (SD)
Lithological Description: Uniform succession of sediments consisting generally of ill-sorted, silt-size quartz grains irregularly distributed in a matrix of very fine silt and clay, with subordinate discontinuous units of well-sorted siltstone.
Definition of Lower Boundary: Taken where the characteristic finer-grained "banded-facies" (Rickards, 1964) of the underlying Bannisdale Slate Formation passes vertically or laterally into ill-sorted siltstones.
Definition of Upper Boundary: The upper boundary is taken at the incoming of the massive siltstones of the Kirkby Moor Flags.
Thickness: c.200m in type area: thin northwards to less than 50m in the Staveley Syncline; increase eastwards to a maximum of c. 900m.
Geographical Limits: Not defined.
Parent Unit: Kendal Group (KNDL)
Previous Name(s): Bannisdale Slates [Obsolete Name And Code: Use BND] (BASL)
Passage Beds (-3236)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Typical sections, showing up to 15m, exposed east of Underbarrow. (Sheet 39 Kendal). 
Reference(s):
Shaw, R W L. 1971. The faunal stratigraphy of the Kirkby Moor Flags of the type area near Kendal. Westmorland. Geological Journal, Vol.7, p.359-380. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E039