Editing Crinoid (section)

===Fossils===
[[File:Fossil_Crinoids.jpg|thumb|Fossil crinoids, Henan Geological Museum, Zhengzhou, China]]
Some fossil crinoids, such as ''[[Pentacrinites]]'', seem to have lived attached to floating driftwood and complete colonies are often found. Sometimes this driftwood would become waterlogged and sink to the bottom, taking the attached crinoids with it. The stem of ''[[Pentacrinites]]'' can be several metres long. Modern relatives of ''Pentacrinites'' live in gentle currents attached to rocks by the end of their stem.

In 2012, three geologists reported they had isolated complex organic molecules from 340-million-year-old ([[Mississippian (geology)|Mississippian]]) fossils of multiple species of crinoids. Identified as "resembl[ing ...] [[aromatic]] or [[polyaromatic]] [[quinone]]s", these are the oldest molecules to be definitively associated with particular individual fossils, as they are believed to have been sealed inside ossicle pores by precipitated calcite during the fossilization process.<ref>{{cite journal |doi=10.1130/G33792.1 |title=Isolation and characterization of the earliest taxon-specific organic molecules (Mississippian, Crinoidea) |journal=Geology |volume=41 |issue=3 |pages=347 |year=2013 |last1=O'Malley |first1=C. E. |last2=Ausich |first2=W. I. |last3=Chin |first3=Y.-P. |bibcode=2013Geo....41..347O }} Note that the first sentence of the phys.org article contradicts the paper itself, which reviews several isolations of molecules from particular fossils over the past decade.
*{{cite web |author=Pam Frost Gorder |date=Feb 19, 2013 |title=Ancient fossilized sea creatures yield oldest biomolecules isolated directly from a fossil |website=Phys.org |url=http://phys.org/news/2013-02-ancient-fossilized-sea-creatures-yield.html}}</ref>

Crinoid fossils, and in particular disarticulated crinoid columnals, can be so abundant that they at times serve as the primary supporting clasts in sedimentary rocks.{{citation needed|date=May 2020}} Rocks of this nature are called [[encrinite]]s.