Aulopora Corals on Brachiopods

Included in this posting are pictures of Aulopora sp. coral fossils that colonized a brachiopod shell surfaces. It was attempted to clean the corals using sand abrasive air cleaning but that was with limited success.  The process took too long to remove matrix from the corals and at times would detach them from the shell.  This matrix of Silica Shale is some what harder than found on similar corals from southern Indiana.

As a comparison to the Silica Shale, the next two images are Aulopora sp. corals encrusted on a Spinocyrtia euruteines brachiopod from the Silver Creek Member, North Vernon Limestone of Clark County, Indiana USA.  This limestone matrix is softer and these Devonian fossils are composed of a reddish-purple colored material.

Here are some corals growing on a Spirifer brachiopod.

If you click on the last to pictures to see the full image size and then magnify portions of the fossil, one can see some micro coral colonies that formed on both sides of the shell.

Thanks to Kenny for doing some prep work on these fossils.  The Silica Shale fossils belong to Dave at the Views of the Mahantango blog.  Learn more at his blog post: CLICK HERE TO VIEW

Micro Trilobites

The trilobite fossils shown are small enough that a microscope is needed to study their details.  Pictures were taken with 23x magnification which is a field of view of about 8 mm.  The trilobites appear to be Devonian and may be Phacops.

This next picture shows the matrix plate which is about 6 cm in width.  The intact trilobite photographed through the microscope is toward the center of the picture.

Next two pictures are of what appears to be a Phacops cephalon.  The compound eye can be seen in some detail.

Also found on the plate is a trilobite imprint.

Thanks to Kenny for his prep work on this very small trilobite. The fossils belong to Dave at Views of the Mahantango blog.

Calymene Trilobite Polished

Here is the trilobite fossil shown in yesterday's post after it has been polished with a buffing wheel.  Since this trilobite shell appears to be a molt and began to dearticulate it does not appear that the matrix can be removed between some of the thorax segments.

This Calymene trilobite is from the Waldron Shale (Middle Silurian Period, Wenlockian stage) of Clark County, Indiana USA. The genus Calymene was named by Brongniart in 1822.

Thanks again to Kenny with help with sand abrasive work to help clean off the glue residue and mini-scribe work to reveal more detail on the cheeks.

If there had been internal remnants of a trilobite it might have looked something like below. It is a drawing done back in 1920 by Dr. Elvira Wood of the Calymene senaria Conrad.