Wavy Cryptozoan rosemontensis Ordovician Stromatolites
Lower Ordovician (495 million
5.5 by 3.5 inches maximum
Site: Oneota Formation, Monroe County, Wisconsin
Coming from the Lower Ordovician Oneota Formation, it is some
495 million years old, from a time that Prokaryotic life forms
no longer had exclusive use of earth's shorelines. Concomitantly,
the earths coastal habitats had markedly reduced stromatolite
reafs, compared with the Proterozoic.
this time in geological history, microbial communities consisted of complex consortia
of both prokaryotic and eukaryotic forms with diverse metabolic needs, and competition
for resources and differing motility among them made for an intriguing microcosm
of interacting life, some autotrophic, some chemotrophic and some heterotrophic.
particular specimen has been cut horzontally thus revealing wavy laminae. Note
how the fine hand polishing reveals the stromatolitic growth history in a beautiful
Click to enlarge