I was recently researching fossils of Minnesota on the web and found this article:
http://www.sciencebuzz.org/blog/collecting-fossils-minnesota
If you scroll down you will see that the author speculates that he has found a baculites in the Ordovician Decorah Shale near Cannon Falls.
There are NO BACULITES in the Ordovician!
Here is a page from the PDF Guide to Fossil Collecting in Minnesota. Excellent little publication that you should download.
Common Cephalopods of Minnesota
Just click on the picture to make it larger.
This is from Wikipedia:
Confusion with Baculites
Orthoceras and related orthoconic nautiloid cephalopods are often confused with the superficially similar Baculites and related Cretaceous orthoconic ammonoids. Both are long and tubular in form, and both are common items for sale in rock shops (often under each other’s names). Both lineages evidently evolved the tubular form independently of one another, and at different times in earth history. Orthoceras lived much earlier (Middle Ordovician) than Baculites (Late Cretaceous) The two types of fossils can be distinguished by many features, most obvious among which is the suture line: simple in Orthoceras, intricately foliated in Baculites and related forms.
Belemnitida (or belemnites) is an extinct order of cephalopods which existed during the Mesozoic era, from the Hettangian age of the Lower Jurassic to the Maastrichtian age of the Upper Cretaceous. The belemnite is the state fossil of Delaware.
Belemnites is a genus of an extinct group of cephalopods belonging to the order Belemnitida. These cephalopods existed in the Early Jurassic period from the Hettangian age (196.5–199.6 mya) to the Toarcian age (175.6–183.0). They were fast-moving nektonic carnivores.
Be careful not to confuse the scientific name Belemnites of this genus with the common name of the cephalopods included in the extinct order Belemnitida (commonly referred to as “Belemnites”).
