Expanding the Museum’s Devonian Fossil Collection.
In August, the GRPM’s Science Curator, Dr. Cory Redman spent a weekend in the Alpena and Rogers City area collecting fossil invertebrates to expand the Museum’s science Collection. The marine fossils found in this area of Michigan are roughly 385 million years old and come from a period of time referred to as the middle Devonian. During this time, Michigan was located south of the equator at ~30°S latitude, opposed to 44°N latitude where it currently resides. The climate was subtropical and the state was covered by a shallow sea.
A diversity of animals lived within this shallow sea and the conditions allowed for many of the animals to become fossilized including: corals, sponges, snails, nautiloids, echinoderms, trilobites, brachiopods, bryozoans, sharks and fish.
1. Cladoselache – shark
2. Goldringia – nautiloid
3. Viaphacops – trilobite,
4. Hexagonaria – coral,
5. Siphonophrentis – coral,
6. Dolatocrinus – crinoid
7. Kentuckia – fish,
8. Paraspirifer – brachiopod
9. Trachypora – coral
10. Eridophyllum – coral
The Alpena and Rogers City area is well-known for fossil collecting and outcrops of fossiliferous limestone and shale that are exposed along roadcuts, rivers and in stone quarries. During the three days that Dr. Redman was in the Alpena and Rogers City area, he focused on collecting fossils from five rock units: Ferron Point Formation, Rockport Quarry Limestone, Bell Shale, Rogers City Limestone, and the Dundee Limestone – found in two quarries, Calcite and Rockport.
The Calcite Quarry is an active quarry and is considered to be the world’s largest open pit quarry (~8024 acres or 12.5 mi2). It first opened in 1912 and is currently operated by Carmeuse Lime and Stone. Carmeuse’s quarrying efforts focus on the Dundee Limestone, which is composed of ~97% calcium carbonate, making it one of the purest limestones.
The Calcite quarry is also unique because Carmeuse can grant quarry access to nonemployees for geological study and fossil collecting. The quarry’s lead lab technician, Kimberly Montague, was Dr. Redman’s escort. The generosity of the Carmeuse team allowed the Museum team to collect fossils from the Bell Shale and the Rogers City and Dundee limestones.
Rockport State Park is an inactive limestone and gravel quarry that operated from 1914 to 1948 by the Kelley’s Island Lime and Transport Company. The abandoned quarry consists of 300 acres in a 4,000 acre state park. Despite being a state park, up to 25 pounds of fossils can be collected per person, per year. Dr. Redman collected fossils from the Bell Shale, Rockport Quarry Limestone, and the Ferron Point Formation.
The fossils from this year’s field work have not been curated yet, but here are some of the fossils collected last year:
Hexagonaria Coral.
From the Rockport Quarry Limestone.
Fossil Sponge.
From the Rockport Quarry Limestone.
Fossil Brachiopods.
(Emannella sp., Atrypa elegans, & Schizophora striatula) from the Bell Shale in the Calcite Quarry.
Corals.
(Lystiphylloide americanum & Favosites norwoodensis) from the Bell Shale in the Calcite Quarry.
By: Dr. Cory Redman, the GRPM’s Science Curator