Beacon Limestone Formation
{{Short description|Geological formation in England}}
{{Use dmy dates|date=April 2022}}
{{Infobox rockunit
| name = Beacon Limestone Formation
| image = Thorncombe_Beacon_from_Great_Ebb_(geograph_5844987).jpg
| caption = Cliff exposure at Thorncombe Beacon
| type = Geological formation
| age = Upper Pliensbachian–Toarcian Spinatum-lowermost Thouarsense
~{{fossil range|185|175}}
| period = Toarcian
| prilithology = Limestone
| otherlithology =
| namedfor = Thorncombe Beacon
| namedby =
| country = England
| coordinates = {{coord|50.9|N|2.8|W|display=inline,title}}
| paleocoordinates = {{coord|38.4|N|7.4|E|display=inline}}
| unitof = Lias Group
| subunits = Marlstone Rock, Barrington & Eype Mouth Limestone Members
| underlies = Bridport Sand Formation
| overlies = Dyrham Formation
| thickness = Up to {{convert|5|m|ft}}
Averaging <{{convert|1.5|m|ft}}
| extent = Wessex Basin
| area =
| map = {{Location map+ | England
| relief = 1
| width = 250
| float = center
| places =
{{Location map~ | England
| lat_deg = 50.9
| lon_deg = -2.8
| mark = Blue pog.svg
| marksize = 12
}}
}}
| map_caption =
| location_ts = Cliff exposure beneath Thorncombe Beacon
}}
The Beacon Limestone Formation, historically known as the Junction Bed, is a formation of the early Jurassic age (Pliensbachian–Toarcian). It lies above the Dyrham Formation and below the Bridport Sand Formation. It forms part of the Lias Group. It is found within the Wessex Basin and parts of Somerset,{{Cite web |url=http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=BNLS |title=Beacon Limestone Formation |website=BGS Lexicon of Named Rock Units |access-date=2018-03-08}} in England. It is well known for the Strawberry Bank Lagerstätte, which contains the 3-dimensionally preserved remains of vertebrates, including marine crocodyliformes, ichthyosaurs and fish, as well as insect compression fossils.{{Cite journal|last1=Williams|first1=Matt|last2=Benton|first2=Michael J.|last3=Ross|first3=Andrew|date=November 2015|title=The Strawberry Bank Lagerstätte reveals insights into Early Jurassic life|url=http://jgs.lyellcollection.org/lookup/doi/10.1144/jgs2014-144|journal=Journal of the Geological Society|language=en|volume=172|issue=6|pages=683–692|doi=10.1144/jgs2014-144|bibcode=2015JGSoc.172..683W |issn=0016-7649|hdl=1983/a7fc8bb4-889c-4fe9-b049-86d284141316|s2cid=52971056 |hdl-access=free}}
Fossil content
Among others, the following fossils have been reported from the formation:
