Submitted on 2012-11-28 by Joseph Koniecki

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: This specimen is 3.2 cm across.

Photo title: Crinoid calyx

Taxa present: Megistocrinus concavus

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Submitted on 2012-11-28 by Joseph Koniecki

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: This specimen is 3.3 cm tall.

Photo title: Blastoid

Taxa present: Placoblastus obovatus

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Submitted on 2013-01-20 by David Thompson

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: This is a very large example of the caylx of a Megistocrinus multidecoratus from the Thunder Bay Limestone of Partridge point in Alpena. It weighs 7 ounces and is nearly 2 inches high by 3 inches wide, a monster from this location

Photo title: Large Crinoid Caylx

Taxa present: Megistocrinus multidecoratus

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Submitted on 2013-01-20 by David Thompson

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: This nearly complete crinoid is disarticulated in parts of the lower stem and the arms have been scraped it appears. Some of the column may still be hidden under the Bryozoan fronds that make up much of the limestone of the matrix which is 7' by 5 1/4' or 18 cm by 13.5 cm. The crown itself is 1 1/2' or 3 cm high and the arms range from 1/2' or 1.2 cm to 1' or 2.5 cm wide.

Photo title: Another almost complete crinoid on matrix

Taxa present: Aorocrinus cassedayi

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Submitted on 2013-01-20 by David Thompson

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes:

Photo title: Same crinoid but in black and white to show crown detail

Taxa present: Aorocrinus cassedayi

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Submitted on 2013-07-23 by Joseph Koniecki

Location (approximate): Alpena, Alpena, MI

Strat unit: Potter Farm formation

Submitter notes: This blastoid is 1.3 cm tall. The side and top view are of the same specimen.

Photo title: Blastoid

Taxa present: Heteroschisma alatus

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Submitted on 2014-05-16 by David Clark

Location (approximate): Alpena, Alpena, MI

Strat unit: Partridge Point formation

Submitter notes: A small calyx with interesting ornimentation from Partridge Point

Photo title: Botryocrinus thomasi calyx

Taxa present: Botryocrinus thomasi

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Submitted on 2014-07-08 by David Thompson

Location (approximate): Alpena, Alpena, MI

Strat unit: Potter Farm formation

Submitter notes: This is an infested crinoid stem with multiple small borings of a parasitic worm: Myzostomida. This has 9 borings in this one stem section. Not too much is known about these galls or tumors as they are also called. They are not too common.

Photo title: Parasitic gall on crinoid columnal

Taxa present: Myzostomida

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Submitted on 2014-07-08 by David Thompson

Location (approximate): Alpena, Alpena, MI

Strat unit: Potter Farm formation

Submitter notes: The Myzostomida are an order of small marine polychaete worms, which are parasitic on crinoids causing gall swelling and holes but rarely leaving any other trace.

Photo title: Parasitic gall on crinoid

Taxa present: Myzostomida

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Submitted on 2014-10-02 by David Thompson

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: This Megistocrinus shows some wear and tear with a number of nodes damaged. It is 3 cm thick by 5. cm wide.

Photo title: Crinoid calyx

Taxa present: Megistocrinus nodosus

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Submitted on 2014-10-02 by David Thompson

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: Two different sizes of the same species. The larger is in the previous photo, the small one is 3 cm thick by 5. cm wide.

Photo title: Big and small Megistocrinus nodosus

Taxa present: Megistocrinus nodosus

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Submitted on 2019-05-12 by David Thompson

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: Contrast in size of blastoids from same formation.

Photo title: Small & large of same species.

Taxa present: Placoblastus obovastus

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Submitted on 2019-05-12 by David Thompson

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: details of Ambulacra

Photo title:

Taxa present: Placoblastus obovastus

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Submitted on 2014-12-06 by Mike Palescuk

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: Found by Bob Boyd, May 2014

Photo title: Blastoid

Taxa present: Hyperoblastus bassleri

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Submitted on 2015-11-05 by Joseph Koniecki

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: This species is rare in the Traverse Group. This specimen has two of its spines still attached. The gastropod is 4.3 cm across including the spine.

Photo title: Gastropod with spines

Taxa present: Platyceras indianaensis

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Submitted on 2016-02-08 by Joseph Koniecki

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: These corals are not attached at the bottom. It appears that they may have grown up along side of each other and been buried together. The corals are about 10-12 cm in height.

Photo title: Group of Corals

Taxa present: Aulacophyllum hemicrassatum

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Submitted on 2018-03-13 by Joseph Koniecki

Location (approximate): Alpena, Alpena, MI

Strat unit: Norway Point formation

Submitter notes: The brachiopod is 2.7 cm across.

Photo title: Brachiopod

Taxa present: Spinocyrtia clintoni

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Submitted on 2019-09-05 by Nick Katsarelas

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: I had just started collecting in earnest that summer of 2017, and this specimen was lying all by itself on the Partridge Point shoreline. It is 4.75 cm long.

Photo title: Placoblastus obovatus

Taxa present: Placoblastus obovatus

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Submitted on 2019-08-21 by Nick Katsarelas

Location (approximate): Alpena, Alpena, MI

Strat unit: Potter Farm formation

Submitter notes: I retrieved this specimen from a construction site on Bagley Road in 2018. The site is now a credit union. Specimen is approximately 70 mm x 90 mm.

Photo title: Spongophyllum alpenense

Taxa present: Spongophyllum alpenense

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Submitted on 2019-09-25 by Joseph Koniecki

Location (approximate): Alpena, Alpena, MI

Strat unit: Thunder Bay formation

Submitter notes: None

Photo title: Crinoid crown with stem

Taxa present: Gennaeocrinus romingeri

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