Echinoids: Devonian Sea Urchins
The Echinodermata make up a phylum of spiney-skinned invertebrates. Echinoderms of the Devonian Period are abundant world-wide and are particularly notable for the large crinoids which grew attached to the under-side floating logs and reached lengths of several meters. Crinoids are commonly known as "sea lilies" but are actually animals that build stalks by means of a series of stacked columnals. In the Guilmette Formation the presence of echinoderms is most conspicuous as scattered crinoid columnals which litter the rocks. Echinoderms are also present as the class Echinoidea, the sea urchins, which give the phylum its name. These tend to be found only as disaggregated spines and plates in deep water environments of the Guilmette Formation.