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. Compass 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 →
Pennoceras was long thought to be a rare, single-species genus found only in the Appalachian Basin, in the Brush Creek and Pine Creek limestones of western Pennsylvania and the Brush Creek of eastern Ohio. Work, Boardman and Mapes (2007) showed that it is one of the most widespread ammonoids inRead More →
I’ve been busy writing elsewhere, so the posts portion of this website is starting to age. Nevertheless, I have discovered several new things over the past few months, and I wanted to share at least one. I found a large specimen of a member of the Bellerophontidae, but in theRead More →
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 “DescriptionRead More →
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 CreekRead More →
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 areRead More →
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 mostly medium to large coiled nautiloids with compressed whorls whose flanks converge toward a narrow, flattened venter. The whorls barely overlap, leaving onlyRead More →
While extensively researching the Paleozoic shark genus Petalodus, I uncovered many holotype specimens. Yet, in searching, there are still a couple I have been unable to locate. Not finding some is not surprising; all the missing holotypes were described during the 19th century and the 1800s. I have spent theRead More →