Conulariida indet
Phylum Cnidaria (?), Class Scyphozoa, Order Conulariida
Geological Time: Mississippian (~320 m.y.a.)
Size (25.4 mm = 1 inch): Fossil is 85 mm long by 30 mm across Matrix: 135 mm by 135 mm
Fossil Site: Heath Shale Formation, Bear Gulch Limestone, Fergus County, Montana
Fossil Code: BGF378
Price: Sold
 Description:
The Bear Gulch Limestone is a deposit of some 70 square km in extent
and 30 m in depth that has been a source of one of the most diverse
assemblages of fossil fish with some 110 species having been described
over the past 30 years. Most were new to science, and provided
a unique view of the marine environment of Mississippian times.
Fine preservation of both fish and invertebrates is a hallmark
of these deposits, presumably due to an anoxic depositional environment.
This specimen is a Conulariid. Conulariids have been a subject
of speculation for over a century and a half. They ranged from
the
Middle Ordovician to the Triassic. Exactly what they were is still
not settled. Because of their fourfold symmetry, they have often
been placed in the Cnidaria. However, their skeleton was very different
from anything known in the Cnidaria, and they may represent a separate,
extinct phylum The Conulariids had elongated, pyramidal exoskeletons,
made up of rows of calcium phosphate rods. Most were square or
rectangular in cross section, with prominent grooves at the corners.
They lived attached to hard objects by a flexible stalk, and often
lived in groups. They are thought to have been filter feeders;
how they reproduced is not known. This one is found with several
brachiopods and bivalves making for an interesting association
piece. |
