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, 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.

Fossil content Among others, the following fossils have been reported from the formation:

Vertebrates Vertebrates of the Beacon Limestone Genus Species Location Stratigraphic position Abundance Notes Images Hauffiopteryx H. typicus Strawberry Bank Falciferum zone Lectotype: GPIT 1491/4, referred: BRLSI M1399, BRLSI M1400, BRLSI M1401, BRLSI M1403, BRLSI M1404 and BRLSI M1406 partial skeletons Ichthyosaur subsequently suggested to belong to Leptonectes Stenopterygius S. triscissus Holotype: GPIT 12/0224-2 referred: BRLSI M1405, BRLSI M1407, BRLSI M1408 and BRLSI M1409 partial skeletons Ichthyosaur Pelagosaurus P. typus "four isolated skulls and associated postcranial skeletal elements along with two articulated specimens, one of which is a small juvenile" Thalattosuchian Pachycormus P. macropterus BRLSI M1297, BRLSI M1299, BRLSI M1320, BRLSI M1332, BRLSI M1359, BRLSI M1389, BRLSI M1395, BRLSI M1341, BRLSI M1351, BRLSI M1366, BRLSI M1393 Pachycormiform fish Leptolepis Indeterminate BRLSI M1259 complete specimen. in length GB3D Lepidotes Indeterminate in length Caturus Indeterminate "two specimens, including an isolated neurocranium (BRLSI M1288)" Amiiform fish BRLSI

Invertebrates Invertebrates of the Beacon Limestone Genus Species Location Stratigraphic position Abundance Notes Images Trivenapteron T. moorei Strawberry Bank Falciferum zone Dermapterid earwig Fulgoridulum Indeterminate Fulgoridiid planthopper Necrotaulius N. parvulus Necrotauliid Trichopteran Liassogomphidae Indeterminate Odonata Elcanidae Orthoptera Archegocimicidae Hemiptera

References