Local crinoid fossil
Crinoids are marine animals that make up the class Crinoidea of the echinoderms (phylum Echinodermata). Crinoidea comes from the Greek word krinon, "a lily", and eidos, "form". They live both in shallow water and in depths as great as 6,000 meters. Sea lilies refer to the crinoids which, in their adult form, are attached to the sea bottom by a stalk.
Crinoids are characterized by a mouth on the top surface that is surrounded by feeding arms. Although the basic echinoderm pattern of fivefold symmetry can be recognized, most crinoids have many more than five arms. Crinoids usually have a stem used to attach themselves to a substrate, but many live attached only as juveniles and become free-swimming as adults.
There are only a few hundred known modern forms, but crinoids were much more numerous both in species and numbers in the past. Some thick limestone beds dating to the mid- to late-Paleozoic are almost entirely made up of disarticulated crinoid fragments.
Fossilised crinoid columnals extracted from limestone quarried on Lindisfarne, or found washed up along the foreshore, which were threaded into necklaces or rosaries, became known as St. Cuthbert's beads. In the Midwestern United States, fossilized segments of columnal crinoids are sometimes known as Indian beads. Crinoids are the state fossil of Missouri.
Local crinoid fossil
Crinoids are marine animals that make up the class Crinoidea of the echinoderms (phylum Echinodermata). Crinoidea comes from the Greek word krinon, "a lily", and eidos, "form". They live both in shallow water and in depths as great as 6,000 meters. Sea lilies refer to the crinoids which, in their adult form, are attached to the sea bottom by a stalk.
Crinoids are characterized by a mouth on the top surface that is surrounded by feeding arms. Although the basic echinoderm pattern of fivefold symmetry can be recognized, most crinoids have many more than five arms. Crinoids usually have a stem used to attach themselves to a substrate, but many live attached only as juveniles and become free-swimming as adults.
There are only a few hundred known modern forms, but crinoids were much more numerous both in species and numbers in the past. Some thick limestone beds dating to the mid- to late-Paleozoic are almost entirely made up of disarticulated crinoid fragments.
Fossilised crinoid columnals extracted from limestone quarried on Lindisfarne, or found washed up along the foreshore, which were threaded into necklaces or rosaries, became known as St. Cuthbert's beads. In the Midwestern United States, fossilized segments of columnal crinoids are sometimes known as Indian beads. Crinoids are the state fossil of Missouri.