I am finding Pseudorthoceras to be common in the local rocks. I find them often. They are often seen straight on and can be mistaken for crinoid columnials. I also am finding them to be fragile and will readily break apart when attempting to extract them.
I was able to identify them apart from Mooreoceras due to their smaller size and septal neck position. Mooreoceras and Pseudorthoceras are both classified under the Pseudorthoceratidae Family within the Mollusca Phyllum.
Locally these present as dark black with a glossy surface. The plates are generally easy to shatter and separate easily.
I also find these in a shattered cross section embedded in the limestone matrix. They appear to be the crystal shape of a mineral that replaced the original creature, but I am not sure. I often find original shell material in these rocks and it could be that.