What is Rhynie chert?
{{coord|display=title|57|20|12|N|002|50|29|W}} [[Image:Rhynie chert.jpg|thumb|230px|Hand sample of the Rhynie chert.]] [[File:Rhynie chert with Rhynia 1.png|thumb|230px|Surface view of a polished piece of Rhynie chert showing many cross-sections of ''[[Rhynia]]'' stems (axes). [[Scale (ratio)|Scale bar]] is 1 cm.]] [[File:Rhynia stem.jpg|right|thumb|230px|Thin section of a piece of Rhynie chert viewed by transmitted light showing the cross-section of a stem of ''[[Rhynia]]'']] The '''Rhynie chert''' is a Lower [[Devonian]] [[sedimentary rock]], part of the [[Old Red Sandstone]]. It has extraordinary [[fossils]], and is a [[Lagerstätte]]. The [[chert]] is exposed near the village of [[Rhynie]], [[Aberdeenshire]], [[Scotland]]. A second unit, the '''Windyfield chert''', is some 700&nbsp;m away. The Rhynie chert is exceptionally preserved material covered by an overlying [[tuff|volcanic deposit]]. Most of the fossil bed has primitive [[plant]]s (which had [[xylem|water-conducting cells]] and [[sporangia]], but no true [[leaf|leaves]]). There are also [[arthropod]]s, [[lichen]]s, [[algae]] and [[fungi]]. == Significance == === Date === This fossil bed is remarkable for two reasons. First, the age of the site, formed about 410 million years ago.<ref>{{cite journal|author=Rice C.M. | display-authors = etal |year=1995|title=A Devonian auriferous hot spring system, Rhynie, Scotland|journal=Journal of the Geological Society, London|volume=152| issue = 2 |pages=229–250|doi=10.1144/gsjgs.152.2.0229| bibcode = 1995JGSoc.152..229R | s2cid = 128977213 }}</ref><ref>{{Cite web |url=http://www.bgs.ac.uk/nigl/pdf_downloads/2004AnnualReport.pdf |title=Natural Environment Research Council |access-date=2011-03-29 |archive-date=2008-12-17 |archive-url=https://web.archive.org/web/20081217130554/http://www.bgs.ac.uk/nigl/pdf_downloads/2004AnnualReport.pdf |url-status=dead }}</ref> This places it at an early stage in the colonisation of land. Second, the sheer quantity and variety of lifeforms throws a vivid light on the whole [[ecos