| 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 . 1887. The Ordovician rocks of Shropshire. British Association for the Advancement of Science. Report for 1886. Birmingham Meeting 662. |
| 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. |
| 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 |
