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 as
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 due
The monospecific genus Pennoceras has a limited range, the Brush Creek and Pine Creek limestones in Pennsylvania and Ohio. These curious members of the Goniatitida have a maximum diameter of only 37 mm. Miller and Unklesbay named these from specimens in the Carnegie Museum. My own specimen below is from
In the past, this gastropod was known as Bellerophon (Pharkidonotus). The name in parenthesis is due to subgenera naming. In modern gastropod taxonomy, several sub and super-names are used, including unranked groups that don’t fall into a classic hierarchy. McCoy named the family Bellerophontidae in 1852 in the publication “Description
Poterioceras curtum is a Pennsylvanian cephalopod first described by Meek & Worthen in 1860. I originally misidentified these as Ctenobactrites isogramma. This is not the first report of this species in Western Pennsylvania. A report from the Annals of the Carnegie Museum in 1947 features specimens from the Brush Creek
Crosswise cells or rays are typical but often hidden components of the vascular tissue in plans. Fossil plants occur in the shale layers below the Brush Creek limestone. These sometimes preserve incredible detail, including detailed carbon films from plants living over 300 million years ago. While shale plant fossils are
Finding specimens of the paleozoic cephalopod genus Domatoceras in local rocks is difficult. They exist, but the genera Metacoceras and Pseudorthoceras dominate the cephalopod fauna. They are large cephalopods with a narrow venter. The younger whorls are only slightly or not impressed into the umbilical walls. Big shells are hard
While performing extensive research on the Paleozoic shark genus Petalodus, I uncovered many holotype specimens. Yet, in searching, there are still a couple that I have not been able to locate. Not finding some is not surprising, all the missing holotypes were described during the 19th century and the 1800s.