A study from the middle Silurian period in Estonia documented these pits and noted their site-selectivity, which raises questions about the ecological dynamics of crinoids during this time[3].

altered limestones containing crinoid remains, and he considered that these limestones, probably Silurian or Carboniferous in age, were the westward extension of Hooker's limestone. On the other ...

The Paleozoic era's Silurian period saw animals and plants finally emerge on land. But first there was a period of biological regrouping following the disastrous climax to the Ordovician.