Overview |
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marine organisms that first appeared in the early in the middle of the Cambrian
period and that still survive up until the present day. The fossil record shows a
world-wide distribution during the geological past. Crinoids were so abundant in the Paleozoic era
that their remains form vast thickness' of limestone. These great 'forests' of crinoids
probably lived in fairly shallow water. Flower-shaped crinoids have blanketed the seas
periodically for more than 440 million years. They collect food with their 'arms'. Each arm has a double row of tiny appendages, or 'tube feet', lining a mucus tract that runs down to the mouth. Crinoids feed by extending their arms to catch particles that float past. Having caught something, they move it, with their tube feet, up their sticky food grooves and into their mouth. Their menu was limited to organic particles and small organisms suspended in sea water.
http://www.kgs.ukans.edu/Publications/ancient/f21_crin.html The popular names for crinoids are 'sea lilies' (for fixed crinoids) and 'feather stars' (for free-swimming crinoids). Crinoids are members of a group called the Echinoderms which also includes Echinoids (sea urchins) and starfish. |
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Fossil photographs |
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A piece of a lens of crinoid limestone from the bottom of the Crumbly & Pyritic Marls Bed (Bed 120) in the Belemnite Marl section. It shows the cross section star shape remains of fossilised crinoid stems. This is representative of the most common 'crinoid' fossil found on the beach. |
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Another piece of a lens of crinoid limestone from the bottom of the Crumbly & Pyritic Marls Bed (Bed 120) in the Belemnite Marl section, this time a view of the water worn top surface of the lens. You can just make out the thicker stems and the thinner fronds. |
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A selection of star shaped crinoid stems collected from the marl above the Crumbly & Pyritic Marls Bed (Bed 120) in the Belemnite Marl section. Each piece consists of a number of ossicles that are joined together. The more water worn specimens loose the star shape as the edges become rounded. |
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A close up of several ossicles, the non-eroded ones displaying a feather-like surface pattern. |
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Other Crinoid references |
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