Nautiloidea indet
Class Cephalopoda, Subclass Nautiloidea
Geological Time: Mississippian (~320 m.y.a.)
Size (25.4 mm = 1 inch): Orthocone fossil is 105 mm long by 20 mm across Matrix:165 mm by 125 mm
Fossil Site: Heath Shale Formation, Bear Gulch Limestone, Fergus County, Montana
Fossil Code: BGF379
Price: $95.00
 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 an orthocone nautilod
. The orthocones derive their name from their essentially straight
shell; some from the Ordovician and Silurian reached lengths
of 3 meters. Note the darkened spots near the living chamber.
These appear to be related to the jaws and ink sac. |
