Submitted on 2007-03-04 by John Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Hungry Hollow formation

Submitter notes: Platyceras conicum is uncommon in the Hungry Hollow member. Complete specimens are hard to find as the pointed end is fragile and usually found broken off. This is an average size specimen. See scale in photo for size.

Photo title: Gastropod on Matrix

Taxa present: Platyceras conicum

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Submitted on 2007-03-04 by John Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Atractocrinus occurs in the upper Arkona Formation. It is always found as just a calyx and rarely with a tegmen. Only one known specimen is preserved with a small amount of arms. The center specimen is 22mm tall. See scale in photo for size.

Photo title: Crinoid Calyxes

Taxa present: Atractocrinus concinnus

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Submitted on 2007-03-04 by John Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Undescribed ophiuroids. These three are tentatively identified as belonging to the genus Furcaster. Brittle-stars are extremely rare in the formation. See scale in photo for size.

Photo title: Ophiuroid Cluster

Taxa present: Furcaster ? sp.

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Submitted on 2007-03-04 by John Topor

Location (approximate): Thedford, Lambton, ON

Strat unit: Arkona formation

Submitter notes: This anchor-shaped holdfast belongs to the crinoid, Ancyrocrinus bulbosus. The holdfasts are uncommon finds and even these five specimens are preserved without their pointed tips. Ancyrocrinus crinoids, found as calyxes or crowns, are extremely rare in the Arkona fm. There are only three known calyxes and no crowns have been found. The largest specimen in the photo is 40mm and the smallest is 15mm in height.

Photo title: Crinoid Anchors (Holdfasts)

Taxa present: Ancyrocrinus bulbosus

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Submitted on 2007-03-05 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Hungry Hollow formation

Submitter notes: Alveolites is common in the Hungry Hollow member. This distinct colony coral is disc-shaped. This specimen is large for the species. Generally, younger specimens will exhibit a smoother surface. This un-cleaned coral shows patches of shale on its surface. A tiny colony of Botryllopora socialis has made a home on the shale near the center of the colony. You will need to zoom in to see it. The coral measures 135mm x 115mm and is approximately 45mm thick.

Photo title: Colony Coral

Taxa present: Alveolites goldfussi, Botryllopora socialis

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Submitted on 2007-03-05 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Hungry Hollow formation

Submitter notes: This horn coral from the Hungry Hollow member is not common in the formation. This specimen is a very fine example. The coral is approximately 85mm long with a cup diameter of 45mm.

Photo title: Solitary Coral

Taxa present: Bethanyphyllum robustum

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Submitted on 2007-03-05 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Hungry Hollow formation

Submitter notes: The photo shows three different views of three specimens. On the left is the top view showing the tegmen, the center shows a side view of the plate ornamentation, and on the right shows the stem attachment area. Of all the crinoids that occur in the formation, your best chance is finding this Dolatocrinus sp. However, all crinoids in the Hungry Hollow member are rare. See scale in photo for size.

Photo title: Crinoid Calyxes

Taxa present: Dolatocrinus bulbaceous

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Submitted on 2007-03-05 by Mike Topor

Location (approximate): Thedford, Lambton, ON

Strat unit: Hungry Hollow formation

Submitter notes: Heliophyllum halli comprises the bulk of the solitary coral species found in the “coral zone” of the Hungry Hollow member. They are the most common coral to be found there. These two specimens are slightly smaller than average, but show the general form well. The diameter of the specimen on the left is 39mm. The length of the coral on the right is 67mm and the width is 42mm.

Photo title:

Taxa present: Heliophyllum halli

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Submitted on 2007-03-05 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: A partial crown from the Arkona fm. Surrounded by stem fragments of the same species. Extremely rare! See scale in photo for size.

Photo title: Crinoid

Taxa present: Melocrinus

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Submitted on 2007-03-05 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Hungry Hollow formation

Submitter notes: Trilobite fragments in the Hungry Hollow member are common, but complete prone specimens are very rare due to the jumbled density of corals, etc. in the “coral zone”. This trilobite’s pygidium was beginning to tuck under when burial took place. See scale in photo for size.

Photo title:

Taxa present: Eldredgeops (Phacops) rana rana

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Submitted on 2007-03-05 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Three different specimens of Proctothylacocrinus berryorum: one showing a portion of the anal sac and another with a partial stem are included in the photo. This species occurs in the upper Arkona fm. Very rare! See scale in photo for size.

Photo title: Crinoid Calyxes

Taxa present: Proctothylacocrinus berryorum

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Submitted on 2007-03-06 by Mike Topor

Location (approximate): Thedford, Lambton, ON

Strat unit: Hungry Hollow formation

Submitter notes: Views of the pedicle and brachial valves of two different specimens of the species. Rhipidomella vanuxemi is smaller than R. Penelope and not as common. The brachial valve is on the left and the pedicle valve on the right in the photo. These brachiopods are approximately 8mm thick. See scale in photo for size.

Photo title: Brachiopod

Taxa present: Rhipidomella vanuxemi

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Submitted on 2007-03-06 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Hungry Hollow formation

Submitter notes: Views of the pedicle and brachial valves of three different specimens of the species: The top row is one specimen with the valves separate, each showing internal structure. The bottom row is two different brachiopods with exterior views of the pedicle valve (left) and the brachial valve (right). The pedicle valve of the internal view is also on the left side of the photo. They are much larger than P. vanuxemi and common in the formation. The two specimens on the bottom row are approximately 8mm thick and 35mm wide x 36mm high.

Photo title: Brachiopod

Taxa present: Rhipidomella penelope

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Submitted on 2007-03-06 by Alex Fabian

Location (approximate): Alpena, Alpena, MI

Strat unit: Traverse formation

Submitter notes: Here is a colony of blastoids occuring on a small lense. The lense is composed of disarticulated blastoid brachioles and stems. This preservation is unique to the Givetian of the Great Lakes region. (aka Hyperoblastus cooperi)

Photo title: Blastoid Hyperoblastus americana (Barris, 1883)

Taxa present: Hyperoblastus americana

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Submitted on 2007-03-06 by Alex Fabian

Location (approximate): Alpena, Alpena, MI

Strat unit: Traverse formation

Submitter notes: A good Specimen measuring 4 cm

Photo title: Cephalopod

Taxa present: Tornoceras uniangulare

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Submitted on 2007-03-08 by David Thompson

Location (approximate): Milan, Washtenaw, MI

Strat unit: Silica formation

Submitter notes: This image compares the structure & size of Microcyclus thedfordensis with the small corals, Pleurodictyum (Procteria) cornu from the Michigan Silica formation. A. is an example of the Microcyclus from the Thedford area of Ontario, B. shows three examples of the Pleurodictyum, two with the upper multi-coralite side showing & the third showing the under side of another example. Unlike the Microcyclus, the Pleurodictyum does not start by attaching to anything. C. is a slightly larger example of the Pleurodictyum from the Bell Shale in Rockport, MI. Mike Toper has other examples on this site of Microcyclus. The U.S. ten cent piece is for scale.

Photo title: Tiny coralites

Taxa present: Microcyclus thedfordensis, Pleurodictyum (procteria) cornu

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Submitted on 2007-03-08 by David Thompson

Location (approximate): Milan, Washtenaw, MI

Strat unit: Silica formation

Submitter notes: This is another species of 'spirifer' Brachiopod from the Silica formation. This top view shows 4 inarticulate brachiopods, Petrocrania hamiltoniae, clustered on the top valve on one side only along with Aulopora corals. There is an additional inarticulate on the underside also which may indicate that this end was above the substrate and allowing the epifauna to live in this area.

Photo title: Spirifer Brachiopod with inarticulates

Taxa present: Mediospirifer audaculus, Petrocrania hamiltoniae, Aulopora

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Submitted on 2007-03-08 by David Thompson

Location (approximate): Thedford, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Here is another example of the crinoid holdfast/anchor/grapnel, Ancyrocrinus bulbosus, from the Thedford area of Ontario. This is from the Arkona Shale at the Microcycus layer. What is unusual is the way I found these two parts. The grapnel with it's four arms was found in a wash area one year. I had the extrordinary good luck to find the stem piece the following year! This almost never happens especially with small fossils requiring you to look on hands & knees. What is even more extraordinary, I was able to actually recognize the connection & pick it up!

Photo title: Another Crinoid Grapnel

Taxa present: Ancyrocrinus bulbosus

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Submitted on 2007-03-08 by David Thompson

Location (approximate): Thedford, Lambton, ON

Strat unit: Arkona formation

Submitter notes: The two parts united for the complete holdfast.

Photo title: The parts together

Taxa present: Ancyrocrinus bulbosus

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Submitted on 2007-03-09 by David Thompson

Location (approximate): Sylvania, Lucas, OH

Strat unit: Silica formation

Submitter notes: This Flexible crinoid from the Sylvania Silica formation is a good size for this species. These are not common. Ten Cent piece & fingers are for scale.

Photo title: Silica Crinoid

Taxa present: Eutaxocrinus wideneri

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