Computer Code: |
HVG |
Preferred Map Code: |
notEntered |
Status Code: |
Index Level |
Age range: |
Caradoc Series (O4)
— Caradoc Series (O4) |
Lithological Description: |
[Obsolete: use HGY] Crystal and lithic tuffs, agglomerates, breccias with thin interbedded shales. |
Definition of Lower Boundary: |
Drawn at the base of the Hayley Ash Formation where it rests conformably upon the Aldress Shales Formation of the Aldress Group. |
Definition of Upper Boundary: |
Drawn at the conformable upward passage from volcanics of the Hagley Volcanic Group to shales of the Hayley Shales Formation. |
Thickness: |
106 metres approx. |
Geographical Limits: |
Chirbury, West Shropshire, England. |
Parent Unit: |
none recorded or not applicable
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
Hagley Volcanic Formation
|
Stratotypes: |
Type Area |
Hagley Quarry, near Chirbury. |
Reference(s): |
Lapworth, C, 1916. Palaentological Work. Summary of progress for 1915. p.36. |
Williams, A and others, 1972. A correlation of Ordivician rocks in the British Isles. Geological Society of London Special Report No.3. |
Lapworth, C . 1887. The Ordovician rocks of Shropshire. British Association for the Advancement of Science. Report for 1886. Birmingham Meeting 662. |
Whittard, W F. 1931. The geology of the Ordovician and Valentian rocks of the Shelve Country, Shropshire. Proceedings of the Geologists' Association, Vol.42, 322-344. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
none recorded or not applicable |