Heteroschisma canadensis from Hungry Hollow

Heteroschisma canadensis is the last of the three blastoid species that I've found at Arkona. It's the smallest and is often referred to as "ice cream cones". As you can see they are about the size of rice grains so one has to be looking really close to find them. All four specimens that I found came by sifting through some eroded gravel.

Oral surface (top)

Side views

Basal surface (where the stem attached)

The other two species that I have from Arkona are Nucleocrinus elegans and Hyperoblastus reimanni. All three were found in the Hungry Hollow member of the Widder formation (Devonian, Givetian stage).

Aulocystis coral from Arkona

Below are some pieces of Aulocystis from the Hungry Hollow member of the Widder formation (Devonian, Givetian) near Arkona. They are often found as loose pieces in the weathered rubble.

There are three species of Aulocystis listed in the Checklist for the Hungry Hollow member of the Widder formation: A. dichotoma (Grabau), A. intermedia (Nicholson) and A. "nobilis". Of the three, A. dichotoma seems to be the best fit based on this illustration from Grabau's classic "Geology and Paleontology of Eighteen Mile Creek".

Note that Aulocystis was once called Ceratopora.

Here are some clusters of Aulocystis auloporidea that I found in the Silica Shale.

Hederella from Arkona

While washing some Mucrospirifer fossils that I'd found at Arkona I noticed a few had some of the Bryozoan Hederella that had grown on them. I have not found many brachiopod specimens with this association at Arkona, usually it's only on Horn corals.

A plate of Mucrospirifer but only one has Hederella growing on it.

A loose Mucrospirifer specimen has some growths too.

Another piece of a shell with some Hederella growths on it.

The Mucrospirifer fossils came from the Widder formation while the partial shell fossil came from the Hungry Hollow member. Both are Devonian, Givetian stage, in age.

Actinopteria from Arkona

Below is a relatively well preserved Pelecypod shell from an Actinopteria that I found at Arkona. It came from the Hungry Hollow member of the Widder formation which is Devonian (Givetain stage) aged. Pelcypod shells tend to dissolve faster in the rock since they are made of Aragonite so it's rare to find one that is intact or complete and this fossil may be just a mold of the original. This specimen shows some fracturing and warping of the shell on the top left side which may have occurred as the sediment compacted.

Based on this checklist, that I'm using to ID fossils from Arkona,I am going to call this an Actinopteria boydi.

Strophodonta from Arkona

Despite the Widder formation being roughly equivalent to the Silica Shale of Ohio and Michigan, Strophodonta is an uncommon fossil to find. When found they are often much smaller as well. Below is a specimen I found in July on a visit to Arkona. It's still embedded in the matrix and I'm hesitant to try and break it out for fear of shattering the fossil.

Strophodonta demissa is known from the Hungry Hollow member of the Widder formation from whence this fossil came. I know that this is not a Protodouvillina inaequistriata because the ribs that decorate the surface are more numerous and thicker.

Here are some Strophodonta from the Silica Shale that I blogged about before.