A recent discovery of a site with abundant roughly preserved Strobeus shells has piqued my curiosity for cutting them open to see the internal structure. The site occasionally preserves material with intact shells, but they are brittle and can shatter easily. During regular mashing of the limestone, they become disconnected,Read More →

Peripristis is a monotypic genus of fish known from Carboniferous rocks, belonging to the Pristodontidae Woodward, 1889. It could be called a form genus, as only isolated teeth are known today. The species semicircularis derives from its curved nature, which represents a portion of a circle. Ginter (2010) and LundRead More →

Mahoningoceras

I started my research thinking this fossil was Mahoningoceras Murphy 1974, then later thought it was smashed, had straight flank sutures, and was a Millkoninckioceras Kummel 1963. I reversed this decision again after comparing it to Millkoninckioceras and refocused on Mahoningoceras. Yet, I received a photo of the holotype fromRead More →

The gastropod Bellerophon nodocarinatus (=Euphemites nodocarinatus) was named by Hall in 1858 in a geological report of Iowa. The name means knotty/lumpy kneels (or carina), characterized by the dual lumpy ridges visible from the anterior margin across the shell. Members of Euphemites have spiral lirae that appear in the aperture and extend toward theRead More →

The Vestigastropoda is a subclass of gastropods that live only in marine environments and have a nacreous layer. The group includes members of the superfamily Pleurotomarioidea, known for shells featuring a selenizone. The selenizone is a slit feature on shells that the living creature uses to aim its exhalant current.Read More →

The Earth’s North magnetic pole has long been an essential tool for navigation. Compas needles with one side magnetized always point towards this magnetic pole, and early people thought a magnetic island existed somewhere in the great cold North. William Gilbert (1600, De Magnete) proposed that the Earth acted asRead More →

The brachiopod Isogramma Meek and Worthen (1870) is challenging to identify when found by inexperienced collectors. These fossils appear as a half circle of sharp, equal-spaced concentric growth lines. All specimens appear flattened, making them difficult to identify as dimensional brachiopod shells. The shells are concavo-convex in life, but dueRead More →

Update: This is not a monospecific/monotypic genus. Some additional species are recently described in the mid-continent. I will add the references when I get time. The monospecific genus Pennoceras has a limited range, the Brush Creek and Pine Creek limestones in Pennsylvania and Ohio. These curious members of the GoniatitidaRead More →