The BGS Lexicon of Named Rock Units — Result Details
Portway Formation
| Computer Code: | PWG | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Ediacaran Period (AD) — Ediacaran Period (AD) | ||
| Lithological Description: | Purple and greenish grey shaly mudstones and siltstones with sandstone bands, sandstones are locally massive particularly near the base. | ||
| Definition of Lower Boundary: | Drawn at the base of the Huckster Conglomerate where pebble horizons with coarse sandstone rest conformably upon purple mudstone, siltstones and sandstones of the Lightspout Formation. | ||
| Definition of Upper Boundary: | Drawn at the conformable upward passage of purple and green shaly siltstones and sandstones of the Portway Group into more massive coarse-grained purple and grey sandstones of the Bayston-Oakswood Formation. | ||
| Thickness: | Averages 625 m. | ||
| Geographical Limits: | The Port Way on the Longmynd, west of Church Stretton, Shropshire. | ||
| Parent Unit: | Stretton Group (YST) | ||
| Previous Name(s): | Portway Group [Obsolete Name and Code: Use PWG]
(-1781)
Portway Formation [Obsolete Code: Use PWG] (YSP) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | The Port Way on the Longmynd, west of Church Stretton, Shropshire. | ||
| Reference(s): | |||
| Greig D C, Wright, J E, Hains, B A and Mitchell, G H. 1968. Geology of the country around Church Stretton, Craven Arms, Wenlock Edge and Brown Clee. Memoir of the Geological Survey, Sheet 166 (England and Wales). (London: H.M.S.O.). 379pp. | |||
| Bright, J E. 1968. The geology of the Church Stretton area. Explanation of 1:25,000 geological sheet SO49. British Geological Survey. | |||
| Lapworth C and Watts W W. 1910. Shropshire. 739-769 in Geology in the field; the Jubilee Volume of the Geologists' Association (1858-1908). Monckton H W and Herries R S (editors). (London: Edward Stanford). | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| none recorded or not applicable | |||