|mhorn||Дата: Wednesday, 18.02.2015, 17:20 | Сообщение # 1|
|King A. (2010) Fossil nautiloids from the Upper Lias (Toarcian) 'junction bed' of the Ilminster area, Somerset // Proceedings of the Somerset Archaeological and Natural History Society. Vol.154. P.249-258. |
The Upper Lias ‘Junction Bed’ (Toarcian, Lower Jurassic) in Somerset has long been known as a rich source of fossils, especially ammonites, brachiopods, bivalves and belemnites. Fossil nautiloids also occasionally occur, but are less common than other molluscs. Three species of fossil nautiloid (belonging to the Order Nautilida) – Cenoceras astacoides (Young and Bird 1828), Cenoceras jourdani (Dumortier 1874) and Cenoceras terebratum (Dumortier 1874) – are described here from the Junction Bed of the Ilminster area. All three species are relatively well known and established within the geological literature, but this is the first time they have been ‘formally recorded’ from Somerset. The specimens mainly comprise internal moulds of septate phragmocones, but several retain traces of body chamber, external shell and ornament.
Middle Jurassic - Lower Cretaceous ammonites & aptychi