the fossils
cephalopod
straight shell · the nautilus's ancient cousin
The tell
A straight tapering cone divided into chambers by walls across its width. Horn coral is curved and has ribs, not chambers.
Orthocones: straight-shelled nautiloids, cousins of the modern nautilus rather than ancestors of the squid. Some grew to several feet.
What it gets mistaken for
- horn coral
- crinoid
- gastropod
- stick
- concretion
The facts
- also calledstraight shell · the nautilus's ancient cousin
- age~385 million yrs
- where it turns upAlpena Co. best · scarce statewide float
- the field marka straight cone crossed by chamber walls
10% of every order goes to northern Michigan animal shelters.