This specimen resided in the late GORDON WALKDEN collection. Fossils, such as brachiopods and crinoids associated with a shallow sea environment, can be found in the rock. It is named after Hunts Bay on the Gower peninsula. The ammonite's keel is absolutely wonderful and very sharp to the touch. Hunts Bay Oolite is an oolitic Carboniferous limestone geological formation found in the south Wales region. This fantastic example was discovered in the winter of 1999 after huge storms battered the south coast. A really nice drawer fossil for the collector. The reef is circular with a steep side to the north. The buildup at Conley field is 300 400 ft (91 122 m) thick over a pre-Palo Pinto high which localized reef growth.

The detail on the ammonites surface is fantastic. fusulinid-oolite packstone is the stratigraphic top of the sequence and represents the end of a shoaling upward phase of deposition. These gault clay ammonites are becoming increasingly scarce thesedays. A wonderful and rare addition for the ammonite collector.Ī lovely double sided specimen with a hint of natural irridescence on the surface. The specimen shows lovely brown hues and has an immaculate centre. The nodule has been broken on collection however, there has been a virtually invisible repair. It contains a few tens of skeleton fragments (holdfasts and columnals) of indeterminate articulate crinoids belonging to the order Millericrinida. The ammonite exhibits its typical rope like keel, which is a distinquishing feature. The studied crinoid material comes from the top part of the upper oolite unit and was collected from the lower exploitation level in the large cement plant quarry at Maiogoszcz. Preserved in a beautiful round nodule is this exquisite example of this very popular and highly sought after ammonite. The Lower Jurassic is made up of the Lias Group, the Middle Jurassic Rocks are divided into the Inferior Oolite Group, and the Great Oolite Group and the Upper Jurassic is represented by the Ancholme Group. More photographs are available in 'Showcase Fossils'. The rocks that form the Cotswolds are made up of three different stages of the Jurassic period and date from between 210-140 million years ago. The overall size of the piece is 36cm x 26cm. The specimen has a cut base with felt attached and makes a fantastic aesthetic display specimen. Many hours of careful preparation have gone into revealing not just only the main ammonite but the small ammonites and the fabulous belemnites which really add aesthetics to this piece. The shape seen is an impression of the shell, the shell itself has been lost through geological processes.Found in the 1980's is this exceptional and very rare ammonite from this well known oolite locality. Fossils found include the ammonite Kosmoceras (Picture 11) as well as small bivalves. This part of the rock succession is organic rich and this helped in the firing of the bricks. The manufacture of bricks ceased in 1969. This clay was exploited in the past at Crookhill brickworks. Although crinoids have the appearance of plants and are sometimes called ‘sea lilies’ they are in fact invertebrates, being related to sea urchins and starfish. Here the clay splits into thin layers along the bedding planes and form what is known as a shale. The most famous of these is a crinoid Apiocrinus. In Picture 9 you may also observe that the strata is dipping gently to the left (south) as it is on the southern side of the anticlinal fold.įurther south at Chickerell Hive Point there are exposures of Oxford Clay. 225 Though the Oxfordian global oolite peak had promoted iron-oolite precipitation, the Kachchh Basin counterpart shows the development of calcitic ooids that were in equilibrium with calcitic seas typical of the Jurassic period. The cornbrash is in a very exposed position on the foreshore 11 Depositional and Diagenetic Environments of the Dhosa Oolite Member. However, it does demonstrate a feature called honeycomb weathering (Picture 10) due to it being rich in carbonates which are attacked by the acid naturally present in rain. This rock contains fossils but they are not very well preserved. Further south along the Fleet landshore in Butterstreet Cove there are exposures of the next younger rock on the succession called cornbrash (Picture 9). The studied crinoid material comes from the top part of the upper oolite unit and was collected from the lower exploitation level in the large cement plant quarry at Maiogoszcz.

Crinoid and oolite