The Big Hill Formation is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and the ...

. It preserves

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

dating back to the Ordovician period. A fossiliferous site on the

Stonington Peninsula Stonington may refer to: Places ;Antarctica *Stonington Island, Marguerite Bay ;United States * Stonington, Connecticut (town) **Stonington (borough), Connecticut (incorporated borough) *Stonington, Illinois *Stonington, Indiana * Stonington, Main ...

(in Delta County) includes a

dolostone Dolomite (also known as dolomite rock, dolostone or dolomitic rock) is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite, CaMg(CO3)2. It occurs widely, often in association with limestone and evaporites, thou ...

layer of the Big Hill Formation which has abundant and well-preserved fossils. The most common fossils are soft-bodied medusae (jellyfish), followed by linguloid brachiopods,

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

, and

arthropods Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

(namely chasmataspidids, leperditid

ostracods Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typical ...

, and

eurypterids Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 million years ago. The group is l ...

). This site is considered a Konservat-Lagerstätte, and is commonly referred to as the Big Hill Lagerstätte or Big Hill Biota.

References

* Ordovician System of North America Ordovician Michigan Upper Ordovician Series {{Michigan-geologic-formation-stub

See also

References