Paleontology in Michigan
During the early part of the Paleozoic Michigan was covered by a shallow tropical sea which was home to a rich invertebrate fauna including brachiopods, corals, crinoids, and trilobites.
[5] Accumulations of these corals up to seventy feet thick are known from places like Engadine, Gould City, and Trout Lake.
The northern region has been more productive for Middle Devonian fish fossils, with Alpena, Charlevoix, Emmet, and Presque Isle counties all contributing discoveries.
The less abundant Middle Devonian fishes of southeast Michigan are known from the rocks of Arenac, Calhoun, Huron, Jackson, and Kent counties.
[6] Acanthodian fossils from Michigan are typically isolated specimens of the spines that supported their fins and these are commonly broken.
However, the best preserved specimens of Michiganian acanthodians reveal large eyed generalists who ate plankton in the mid-level of the water column using teeth with multiple points.
Since shark skeletons were cartilaginous and lacked hard parts conducive to fossilization, typically only their spines and teeth remain.
Despite occurring so early in the fossil record, Michigan's cladoselachian sharks closely resembled modern forms.
[7] Fossil lungfish burrows are another interesting find from the Pennsylvanian coal swamp deposits near Grand Ledge in Clinton County but these tend to be poorly preserved.
[1] The ensuing Triassic period of the Mesozoic era is missing from the state's rock record for the same reason as the Permian.
However, these are the only known local fossil from the time period since rocks of this age are buried deep underground and accessible only through core sample drilling.
[8] The same erosional forces responsible for the Permian and Mesozoic gaps in Michigan's rock record were active during the ensuing Paleogene and Neogene periods of the Cenozoic era.
[9] The most common mammals in Michigan's Pleistocene fossil record were caribou, elk, Jefferson mammoths, American mastodons, and woodland muskoxen.
Less common members of Michigan's fossil record included black bears, giant beavers, white-tailed deer, Scott's moose, muskrats, peccaries, and meadow voles.
[10] Among Michigan's early significant fossil finds was the 1839 discovery of the state's first scientifically documented American mastodon remains.
[11] Later in the 19th century was the 1877 discovery of five Pleistocene peccaries (Platygonus compressus) in an Ionia County peat bog located near the town of Belding.
[12] In 1914, Ezra Smith made another interesting Pleistocene-aged discovery, finding the fossil penis bone of a Late Pleistocene walrus seven miles northwest of Gaylord.
In 1927 excavations for a new schoolhouse in Oscoda turned up a Late Pleistocene fossil rib that may have belonged to a bowhead whale of the genus Balaena.
[15] 1930 saw Hussey publish the first scientific paper on the Michiganian whale fossils curated by the University of Michigan Museum of Paleontology.
[16] The fourth decade of the twentieth century was kicked off by the 1940 announcement by MacAlpin that a total of 117 American mastodon specimens had been discovered in Michigan.
[15] He also reported the discovery of an Arkonan-aged[clarification needed (possibly referring to Thedford-Arkona region)] rorqual rib of the genus Balaenoptera.
[18] Handley also reported the discovery of another walrus fossil, a skull catalogued as UMMP 32453 found in a Mackinac Island gravel deposit.
[19] In August of 1961, Larry Kickels collected the third right upper molar of a Jefferson mammoth from a gravel layer 100 feet below the surface of Berrien County, near the town of Watervliet.
On September 18 Larry Kramer discovered a lower mastodon molar now catalogued as GRPM 12540 in Paris Township along Buck Creek.
