Paleontology in Wisconsin

Because of the thick blanket of Pleistocene glacial sediment that covers the rock strata in most of the state, Wisconsin’s fossil record is relatively sparse.

Fossils of many groups of organisms have been found including stromatolites, conulariids, brachiopods, gastropods, monoplacophorans, trilobites, graptolites, and conodont elements.

Wisconsin’s Cambrian rocks have also produced fossils of more aglaspidid (a grouping of arthropods closely related to trilobites) species (around 12) than those of any other state.

Fossils include stromatolites, stromatoporoids, sponges, conulariids, rugose and tabulate corals, bryozoans, brachiopods, gastropods, monoplacophorans, bivalves, nautiloids, trilobites, ostracods, phyllocarids, cystoids, crinoids, graptolites, conodont elements, and jawless fish bones.

"[5] Also of much significance is the Waukesha Biota, which is a Konservat-Lagerstätte famous for its superbly preserved fossils of strange arthropods, worms, and other organisms not previously recorded from Silurian rocks.

While all are fossiliferous to some degree, the youngest is entirely sub-surface, and the others are very limited in exposure and mostly inaccessible, except for occasional glacial erratics found in excavations and along the shore of Lake Michigan.

Its fossil biota includes around 250 species of agglutinated foraminifers, radiolarians, chitinozoans, conulariids, rugose and tabulate corals, tentaculitoids, bryozoans, hederelloids, brachiopods, hyoliths, gastropods, rostroconchs, bivalves, nautiloids, actinoceratoids, ammonoids, annelid worms (scolecodonts), trilobites, ostracods, phyllocarids, crinoids, blastoids, edrioasteroids, graptolites, conodont elements, fishes (placoderms, sharks, acanthodians, sarcopterygians), terrestrial fungi, and land plants (cladoxylopsids?

[9] Rocks of Permian to Neogene age were either rarely deposited in Wisconsin or were eroded away by the Pleistocene glaciers and other erosional agents.

In 1877 research by T. C. Chamberlin uncovered differences in the composition and fossils of the reef-bearing rocks of the Milwaukee area as compared to those that didn't contain reefs.

[5] Lapham, Greene, Teller, Day, and another gentleman naturalist, C. E. Monroe, also gathered extensive collections from the Devonian Milwaukee Formation.

The majority of those fossils came from natural cement quarries that operated between 1876 and 1911 along the Milwaukee River in the area now occupied by Estabrook and Lincoln Parks.

The location of the state of Wisconsin
How earth possibly looked like during the Precambrian eon
A reconstruction of the ecosystem at Blackberry hill , showing a variety of organisms. The purple circle shaped objects are stranded jellyfish , the arthropod on the lower left making the trackway Protichnites is the euthycarcinoid Mosineia , the bigger brown organisms are large slug like mollusks that are the supposed makers of the Climactichnites trails at the site. And the tiny arthropod near the bottom is the phyllocarid Arenosicaris .
A diorama of a typical Ordovician sea floor
A diorama depicting the large Silurian reefs that ran through ancient Wisconsin and Illinois
The Arthrodire Placoderm Holonema rugosum which has been found in Devonian deposits of several states including Wisconsin
Placenticeras , one of the few Mesozoic animals found in Wisconsin
The Hebior Mammoth , found near the small town of Paris, Wisconsin . Currently in the atrium of the Milwaukee Public Museum .
Castoroides lived in many parts of North america, including Wisconsin
Lapham examining a meteorite which had fallen in Wisconsin in 1868
The Silurian trilobite Calymene celebra ; Wisconsin's state fossil.