[1] Once a prolific source of fossils, the Milwaukee Formation exposures are now mostly buried, inaccessible, on private property, or located in areas where collecting is prohibited.

[3] The rock was later used to produce lime or building stone, and in the 1840s, Wisconsin's first resident scientist, Increase A. Lapham, noted the natural cement potential of certain of its layers.

During that time, Lapham also collected fossils from those strata, which caught the attention of James Hall, Thomas Chrowder Chamberlin and other noted American paleontologists and geologists who went on to study the biota.

Quarrying methods at that time required many hands to load rock into the dump cars destined for the kilns.

The formation preserves fossils of marine and terrestrial organisms, including placoderm fish that were the size of great white sharks, some of the first trees, and fungi that may have reached the height of a two-story building.

[1] The Milwaukee Formation is considered to be Givetian in age (~385 mya), as determined by using its biota to correlate the strata with certain portions of the Cedar Valley Group to the west.

[1] Other taphonomic phenomena often found in the Milwaukee Formation are geodization of shelly fossils, corals, bryozoans, and echinoderms, and preservation of color patterns in certain brachiopods, trilobites, and fin spines of fish.

[6][1] The most distinctive feature of the Milwaukee Formation is the diversity of its biota, as measured by the total number of species.

The most species-rich group of the Milwaukee Formation's biota is the Brachiopoda, having around 46 named species and sub-species,[7] followed by the Bivalvia, which has around 43.