The BGS Lexicon of Named Rock Units — Result Details

Plymouth Limestone Formation

Computer Code: PYL Preferred Map Code: PyL
Status Code: Full
Age range: Eifelian Age (DI) — Frasnian Age (DR)
Lithological Description: Comprises irregular masses of fine-grained pale grey stromatoporoid boundstone that pass laterally and vertically into coarse-grained crinoidal packstone and grainstone with scattered stromatoporoids and corals. Erosive floatstone and rudstone beds of reworked and broken coral and stromatoporoid colonies are also present. Beds of fine-grained skeletal packstone interdigitate with normal facies. Red argillaceous calcite mudstone and breccia are found as fissure fill.
Definition of Lower Boundary: Faulted out.
Definition of Upper Boundary: Faulted out.
Thickness: Not known. (This is a reef, which varies from 0 where not developed).
Geographical Limits: Mapped within the city of Plymouth (Sheet 348). Extending eastwards onto the Ivybridge (349) sheet. Discontinuous reef type deposits.
Parent Unit: Tamar Group (TAMA)
Alternative Name(s): none recorded or not applicable
Type Area  Cliff sections and numerous quarry faces around Plymouth Hoe, and between Devil's Point and Eastern King Point. Plymouth Hoe: SX 477 538. 
Ussher, W A E, 1907. The Geology of the country around Plymouth and Liskeard. Memoir of the Geological Survey of Great Britain, Sheet 348 (England and Wales). 
Taylor, P W, 1951. The Plymouth Limestone; and the Devonian tetracorals of the Plymouth Limestone. Transactions of the Royal Geological Society of Cornwall, Vol.18, 146-214. 
Chandler, P and McCall, G J H, 1985. Stratigraphy and structure of the Plymouth-Plymstock area: a preliminary revision. Proceedings of the Ussher Society, Vol.6, 253-257. 
Leveridge B E, Holder, M T, Goode, A J J, Scrivener R C, Jones N S and Merriman, R J. 2002. Geology of the Plymouth and south-east Cornwall area. Memoir of the British Geological Survey, Sheet 348 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E348 E349