Collyrites ellptica

Here is a rather interesting Echinoid from Sarthe, France. It's a Collyrites ellptica from the Jurassic (Callovian) and what makes it odd is the arrangement of the Ambulacra (five arm like shapes). In most irregular echinoids the Ambulacra are arranged in a star like pattern whereas this genus has a large space between sets. I don't know why this is but it certainly lends a unique look to the fossil.

Adapical (top)

Anterior (Front)

Side pofile

Posterior (Rear). The hole is where the anus would have been located.

Adoral (bottom or underside). The hole seen on the adoral surface was where the mouth of the animal was located.

There is another species from this same location called Collyrites dorsalis which is a bit thicker in profile.

Adapical surface

Anterior

Side pofile

Posterior

Adoral surface

For more info on Echinoid anatomy check out the Irregular Echinoid Terminology page at the British Chalk Fossils website.

Trigonia dillatata

The Cretaceous Jurassic (Oxfordian stage) aged cliffs near Villers Sur Mer are the source for these Trigonia dillatata clavellata pelecypods. Trigonia shells can be noted for their unique shape and shell decoration which varies from species to species.

This is a smaller but less worn example of the species.

Thanks to Gery for sending me these specimens and for correcting me on the species and age. I get confused sometimes trying to keep track of the Cretaceous and Jurassic stages. :)

Pictavia bajocensis from Segenthal, Germany

Below is a Gastropod,  Pictavia bajocensis, that was found at Segenthal, Germany. I purchased it from Matthias Weissmueller's E-bay store.

The fossil above comes from Jurassic aged rocks (Bajocian stage) near Segenthal Germany.

Loboidothyris perovalis from Segenthal, Germany

One of the many brachiopods that are found in the Jurassic aged rocks (Bajocian stage) of Segenthal, Germany is Loboidothyris perovalis.

Pedicle valve

Anterior

Brachial valve

Posterior

Profile

Superficially it looks similar to Cererithyris, like the one I wrote about here, but the plications (the wavy folds of the shell most easily seen in the anterior view) are less exaggerated. I purchased the above fossil from Matthias Weissmueller's E-bay store.

Opis similis pelecypod from Segenthal, Germany

Opis similis is a pelecypod found in the middle Jurassic (Bajocian stage) aged rocks at Segnethal, Germany. I purchased it fossils from Matthias Weissmueller's E-bay store.

Right hand valve

Left profile

Left hand valve

Right profile

Anterior

Posterior

Matthias does all his own prep work and really brings out the character of the shells that he finds. I like the overall shape of the shell and that is one of the reasons I purchased it.

Two for one fossil from Segenthal, Germany

Sometimes you get a fossil with some added interest in the form of epibonts or odd growth patterns. This Pseudogarantina ammonite has something a little different, a pelecypod that was embedded it in during deposition or compaction of the sediments.

You only notice the pelecypod once you turn the ammonite around. I believe it's a species called Astarte minima based on the book "Sengenthal - Ein Eldorado für Fossiliensammler - Die Muscheln des Bajocium von Sengenthal" by Matthias Weissmueller from whom I also purchased this specimen from.

You can see that it was pushed into the ammonite shell by the current or waves during a storm. The ammonite shell itself may have been broken during a storm event or had just been exposed on seafloor for a while and was starting to break down.

I like that you can see the teeth along the edges of the pelecypod shell

The fossils found at Segenthal, Germany are found in rocks from the middle Jurassic (Bajocian stage). I purchased my fossils from Matthias Weissmueller's E-bay store.

Sowerbyella brachiopod from the Verulam fm.

Sowerbyella is another common brachiopod in the Verulam formation. It's not as prolific as Dalmanella but can be found in similar layers. Sowerbyella is most easily recognized by the rectangular outline of the smooth, unornamented shell. It has a long hinge line and a concave brachial valve that parallels the convex pedicle valve, as is typical of the Strophomenida order of brachiopods.

Specimen #1
Pedicle valve

Anterior

Brachial valve

Posterior

Profile

Specimen #2
Pedicle valve

Anterior

Brachial valve

Posterior

Profile

Both specimens shown above were collected from the Verulam formation near Brechin, Ontario. The Verulam formation is Ordovician (Katian/Mohawkian) in age.