Fossils From the Silica Formation in Sylvania, Ohio - Trilobites, Brachiopods, Corals




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Silica Shale - Ohio Collecting Page



This New York Site Devonian has nearly the same fossils as the Sillica Shale.



Eldredgeops (Phacops) Facts and Information
Everything you wanted to know about these trilobites!





Sample of Fossils Found in the Silica formation - Devonian of Ohio
Identification Guide

Fossils here include: Trilobites, Brachiopods, Corals,



Trilobites
Eldredgops milleri (Formerly known as Phacops rana)

Like all fossils found in the Silica Formation, Trilobites are exquisitely preserved.
The most common trilobites are Phacops rana. However, complete trilobites are difficult to find. This plate shows how they are more typically found; as bits and pieces.
Preparationn by an air abrasive unit is the easiest way to prep trilos from this formation.


Formation: Silica
Age: Middle Devonian ~370 - 400 m.y
Location: Silvania, OH
Size: The black trilo cephalon (head) is ~1" across (25mm)

Trilobite Fossil From Ohio - Devonian - Eldredgops / Phacops rana
Many other Trilobites in the Silica Formation are enrolled, like this one.

Formation: Silica
Age: Middle Devonian ~370 - 400 m.y
Location: Paulding, OH
Size:~ 1.3" across (34mm)

Enrolled Trilobite Fossil From Ohio - Devonian - Eldredgops / Phacops rana
This is another enrolled Eldredgops (Phacops) Trilobite fossil. This one is a little smashed, as the pygidium (tail) is pushed inside the Thorax.
It has a couple small flakes of pyrite stuck to it.


Formation: Silica
Age: Middle Devonian ~370 - 400 m.y
Location: Paulding, OH
Size:~ 1.4" across (35mm)

Prone Trilobite Fossil From Ohio - Devonian - Eldredgops / Phacops rana
Trilobite Fossil From Ohio - Devonian - Eldredgops / Phacops rana
This a large Eldredgops (Phacops) trilobite. Unfortunately the pygidium (tail) is missing.

Formation: Silica
Age: Middle Devonian ~370 - 400 m.y
Location: Paulding, OH
Size:~ 2.2" across (55mm) - longer if it had the pygidium


Brachiopods
Brachiopods are similar to mollusks, like clams, however, they are not closely related. Unlike most present day mollusks, the two shells of a brachiopod were different sizes.

Brachiopods were the dominant form of life in the seas in most of the Paleozoic, including the Devonian. Therefore, they are a very common fossil of the Devonian coral reefs in Western New York. Dozens upon dozens of species and genera can be found in the fossilized Devonian coral reefs.

Many genera and species Brachippods occur in the Silica Shale, the Devonian of Ohio. Below are a few example fossils.


Mucrospirifer mucronatus (Conrad)
M. Mucronatus is a small to medium sized brachiopod fossil. It is very beautiful in that the hinge line is straight and very long, ending in a spine-like point. The term Mucronate means to end abruptly in a point.
Unfortunately, the mucronate ends are often broken off.

They are very wide, usually 3 or 4 times wider than the height. They have radial striations, and often numerous growth lines are visible.
These are fairly abundant in the Silica Formation.

Formation:
  • Silica
    Age:
  • Middle Devonian ~370 - 400 m.y
    Location:
  • Silvania, OH
  • This is a plate of Mucrospirifers. Plates of these brachiopods are very common, however they take an air abrasive unit to properly prep. Each brachiopod is approximately 2" on this plate.

    Mediopirifer Audaculus (Spirifer Audaculus)

    These fossil brachiopods are more robust looking than M. mucronatus. Also the hinge line is not as straight as in M. mucronatus, and they are less elliptical, in that their width and height are not in as extreme proportions as M. mucronatus. They have more of a semi-circle shape.

    Devonian fossil shell Brachiopod from the Silica Shale of Ohio; Mediospirifer audaculus
    These aer two fossil brachiopods still cemented together with matrix.
    Formation:
  • Silica Shale
    Age:
  • Middle Devonian
    Location:
  • North Western Ohio
  • Stropheodonta Demissa (Conrad)

    This is a medium sized brachiopod fossil. It has an easily identifiable shape, looking like a half-circle. The pedical valve is very convex, while the brachial valve is concave. It also has strong radial striations running the length of both shells.

    There is a very similar looking brachiopod called Megastrophia concava. However, it is much larger in size.

    Devonian fossil shell brachiopod from the Silica formation in Ohio; stropheodonta demissa
    Formation:Silica Shale
    Age: Middle Devonian
    Location: North Western Ohio
    These Stropheodonta brachiopod fossils are fairly common in the Silica Formation.

    Formation:
  • Silica
    Age:
  • Middle Devonian ~370 - 400 m.y
    Location:
  • Silvania, OH
    Size:
  • ~ 2" (51mm)

  • Megastrophia concava

    These giant brachiopods are one of the larger types of Brachiopod fossils found in the Silica shale. They look like Stropheodonta brachiopods, but are MUCH larger.

    Devonian fossil shell brachiopod from the Silica formation in Ohio; megastrophia concava.jpg
    Formation:Silica Shale
    Age: Middle Devonian
    Location: North Western Ohio
    Size: ~2.5" (~64 mm)

    Cnidaria Phylum
    Corals

    The Silica Formation contains a rich variety of corals. The corals easily weather from the shale, and are therefore easy to collected. The genera in the images below include: Bethanyphyllum (Stumm), Heliophyllum (Hall), Heterophrentis (Hall), and possilbly others.
    Horn Corals

    Formation:
  • Silica
    Age:
  • Middle Devonian ~370 - 400 m.y
    Location:
  • Silvania, OH
    Size:
  • ~ (mm)

  • Formation:
  • Silica
    Age:
  • Middle Devonian ~370 - 400 m.y
    Location:
  • Silvania, OH
    Size:
  • ~ (mm)