Submitted on 2007-02-02 by Shanan Peters

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes:

Photo title: Platyceratid gastropod on crinoid calyx

Taxa present: Arthroacantha carpenteri, Platyceras sp.

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Submitted on 2007-02-02 by Joseph Koniecki

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: The spread of the arms is 4 inches at its widest.

Photo title: Complete specimen of Arthroacantha

Taxa present: Arthroacantha carpenteri

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Submitted on 2007-02-02 by Joseph Koniecki

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: The starburst is about 7 inches in diameter

Photo title: Arthroacantha starburst

Taxa present: Arthroacantha carpenteri

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Submitted on 2007-02-03 by John Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Specimen is approximately 30mm in diameter

Photo title: Devonaster Starfish

Taxa present: Devonaster triradiatus

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Submitted on 2007-02-03 by Joseph Koniecki

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Lower spine is 4 cm.

Photo title: Gastropod with spines

Taxa present: Spiniplatyceras arkonensis

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Submitted on 2007-02-11 by Tomasz Baumiller

Location (approximate): Thedford, Lambton, ON

Strat unit: Arkona formation

Submitter notes:

Photo title:

Taxa present: Arthroacantha carpenteri, Platyceras

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Submitted on 2007-02-13 by David Thompson

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: This is the top view of an Arthroacantha carpenteri crinoid calyx showing the anal pyramid with a very pronounced borehole. Again U.S. 10 cent pc. for scale.

Photo title:

Taxa present: Arthroacantha carpenteri

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Submitted on 2007-02-14 by John Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Specimen is 150mm in diameter. The most complete of three known specimens. This species has 28 arms. Note the large madreporite at the 11 o'clock position just outside of the mouth-angle plates.

Photo title: Multi-Armed Starfish

Taxa present: Arkonaster topororum

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Submitted on 2007-02-18 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Certainly one of the most attractive crinoids of the formation. Very Rare! It was described by Winifred Goldring on a specimen that had regenerated arms.

Photo title: Crinoid Crown

Taxa present: Gennaeocrinus mourantae

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Submitted on 2007-02-18 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Corocrinus is the second most common crinoid in the formation behind Arthroacantha. It's distinctive ornamentation and three notches on the basals are characteristic of the crinoid. However, it's placement needs revision. The specimen is 22mm high and 15mm wide

Photo title: Crinoid Calyx

Taxa present: Corocrinus(?) calypso

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Submitted on 2007-02-18 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Corocrinus is the second most common crinoid in the formation next to Arthroacantha. This specimen shows the arm structure. The plates of the calyx are difficult to see because of pyrite. The crown measures 45mm high and 55mm wide.

Photo title: Crinoid Crown

Taxa present: Corocrinus(?) calypso

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Submitted on 2007-02-18 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: This tabulate coral is restricted to the upper part of the formation. The largest of the five specimens shown is 40mm high by 30mm wide. The smallest is 25mm by 25mm.

Photo title: Tabulate Coral

Taxa present: Aulocystis ramosa

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Submitted on 2007-02-18 by Mike Topor

Location (approximate): Arkona, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Top row: Contrasts a very large specimen (20mm) with a very small one (6mm) and 2 average size (12mm) specimens showing top and bottom views. Middle row: First specimen has turned-up margin; the second shows rejuvenation; the third is twins (two growing together); The fourth is encrusted with the Bryozoan, Eliasopora. The fifth is encrusted with Aulopora. Third row: Shows various attachments; #'s 1&2 are attached to trilobite fragments. #3 is attached to a tiny chonetid brachiopod. #4 is attached to a small crinoid columnal, and #5 is attached to a Pelecypod fragment.

Photo title: Button Corals

Taxa present: Microcyclus thedfordensis, Eliasopora stellatum, Aulopora sp., Eldredgeops sp.

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Submitted on 2007-02-18 by Mike Topor

Location (approximate): Thedford, Lambton, ON

Strat unit: Arkona formation

Submitter notes: Occurs high in the Arkona formation in the same horizon as the button coral Microcyclus, but not as numerous. Because of it's shape it's often called the 'slipper coral'. The largest of the six specimens measures 13mm long and nearly as wide.

Photo title: Coral

Taxa present: Xenocyathellus thedfordensis

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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: 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: 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 2007-03-08 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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