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Fossils
Geology of the Hundred of Bradford on Avon, Wiltshire
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A small, but perfect dome-shaped colony of the coral Isastraea, found loose but probably derived from the Bradford Coral Bed. The hollows in which the individual animals lived, with the ridges that supported their internal structure, can be clearly seen. Each animal would have been a clone of the original individual that started the colony.
Dictyothyris coarctata (Parkinson), a terebratulid brachiopod shell that is typical of the Bradford Clay (Middle Jurassic, Great Oolite Series). Brachiopods, of which there are only a few still living today, are shelled animals that lived attached to the sea floor.
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Catinula sp., a type of small fossil oyster that is common in the limestone beds around Bradford (Middle Jurassic, Great Oolite limestone)
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A fossil sea snail called Nerinea with a tightly-coiled tall-spired shell; the top third is missing. It came from a bed high in the sequence of the Great Oolite Series, Middle Jurassic rocks.
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Broken worn pieces of the shell of Chlamys (Radulopecten), a distant relative of today’s scallops, are fairly common in the shelly beds of the Great Oolite. This is a small juvenile, but complete. It has coarse concentric ridges and wide low radiating ridges and the “ears” that extend the hinge-line.
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The top bed of the sequence of limestones of the Great Oolite, just below where the clays of the Forest Marble come in, is known as the Bradford Coral Bed. The fossils it contains conjures up visions of the tropical past of this area 165 million years ago. This is a small colony of the coral Thamnasteria from this layer.
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The bivalve Pholadomya had very thin shells which do not usually survive. This is a natural internal cast in which the ribbing of the exterior is preserved. The animal burrowed into the soft sediment of the sea bed and the fossils have often been slightly distorted as the sediment was compacted and hardened into rock. In this case the rock is part of the limestones known as the Cornbrash, in which Pholadomya is typical and it is one of several found in Loddon Way, off Trowbridge Road in Bradford.
Another fossil bivalve, Grammatodon, that was found in a shelly drift within a piece of white limestone that is mainly composed of ooliths
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Bradford on Avon Museum displays several specimens of fossils -ammonites, sea lilies and Jurassic reptiles- collected in and around Bradford by the Bradford collector Joseph Chaning Pearce (1811-1847). They are on loan from Bristol City Museum & Art Gallery.
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