Reticycloceras sp
Class Cephalopoda, Subclass Nautiloidea, Order Nautilida, Family Pseudorthoceratidae
Geological Time: Mississippian (~320 m.y.a.)
Size (25.4 mm = 1 inch): 72 mm long by 20 mm across Matrix: 90 mm by 55 mm
Fossil Site: Heath Shale Formation, Bear Gulch Limestone, Fergus County, Montana
Fossil Code: BGF36
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 an orthocone
nautilod known as Reticycloceras. The orthocones derive their name
from their essentially straight shell; some from the Ordovician and
Silurian reached lengths of 3 meters. |
