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 Post subject: Ammonites
PostPosted: Sat Aug 01, 2009 12:00 pm 
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Location: uk
Hi everyone

Collected these Ammonities on Tuesday at Port Mulsgrave Bay some ten miles north of Whitby. Actually they are limestone pseudomorphes casts of ammonites containing also calcite and often pyrite. Ammonites existed 240-65 million years ago. They became extinct at the same time as the dinosaurs in the Cretaceous period in the K-T mass extinction. The chambers in the ammonite were linked with each other by a tube and by filling and emptying them with water or air could move through the water. They belong to a group of predators known as cephaloidea. Their living relations are octopus, cuttlefish and nautilus.

Port Mulgrave ammonites are often coated with pyrite. In the 1800's a great deal of ironstone was shipped from here to Middlesborough and Jarrow to produce steel.

Port Mulgrave is now famous for its fossils. The jurassic and cretaceous limestone and shail is exposed. It contains many fossils inluding dinosaur and reptile fossil remains.

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Here are some more pictures taken in my back yard

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Last edited by davegibson on Mon Aug 03, 2009 1:53 pm, edited 3 times in total.

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PostPosted: Sat Aug 01, 2009 12:53 pm 
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8) dave,
really nice ammonites!! in your back yard pics, did you build the wall with the ammonites??

by the way, cuttlefish are strange critters! 8)


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PostPosted: Sat Aug 08, 2009 11:43 am 
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Here is a photo of Port Mulgrave and the abandoned Alum quarry of Kettleness in the distance.

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Here is some information about Kettleness

Marine reptiles - Plesiosaurs, Ichthyosaurs, and crocodiles - swam in the shallow seas of the lower Jurassic period. When they died their remains were preserved in the soft shales that were being formed on the seabed. The shales were lifted up to form part of the landmass of Great Britain but the fossilised bones lay undisturbed for more than 180 million years. Then in the 1600's the shales were found to be a valuable source of a chemical called Alum. As the shale was dug out of the cliffs, thousands of different types of fossils were discovered. In the 1800's people began to understand that these were scientifically and commericially valuable and so they were preserved. The most spectacular finds were the fossilised bones of the great sea reptiles, often 3 to 6 metres in length. Fortunately some of these were bought by local museums and are still still on display.

Hi Gingerkid - I built the wall and added the fossils in later

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PostPosted: Sat Aug 08, 2009 12:37 pm 
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:D excellent information, thanks for sharing, dave!!

by the way, i really admire the fossil wall which you built!! 8) and artistic!!


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