The Matt Formation is an

Early Oligocene The Rupelian is, in the geologic timescale, the older of two age (geology), ages or the lower of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/series (stratigraphy), Series. It spans the time between . It is preceded b ...

-aged marine

geological 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 expo ...

that outcrops in the

Glarus Alps The Glarus Alps () are a mountain range in central Switzerland. They are bordered by the Uri Alps and the Schwyz Alps to the west, the Lepontine Alps to the south, the Appenzell Alps to the northeast. The eastern part of the Glarus Alps contains ...

of the

Canton of Glarus The canton of Glarus ( ; ; ; ) is a cantons of Switzerland, canton in east-central Switzerland. The capital is Glarus. The population speaks a variety of Alemannic German. The majority of the population (81%) identifies as Christianity in Switzer ...

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

. It is most notable for its fossiliferous slates found near Engi, known as the Engi slates, Glarner Schiefer (Glarus Slate) or Glarner Fischschiefer ("Glarus fish slate"), which contain the well-preserved fossils of fishes, birds, and sea turtles. The metamorphization of the rock has led to many of the fossils appearing somewhat distorted.

Geology

The Matt Formation is divided into two sections: a lower member of turbiditic sandstones (Matt Sandstones) and the upper Engi Slates, which contain the famous fossil fishes. As with other formations along the

Glarus thrust The Glarus thrust () is a major thrust fault in the Alps of eastern Switzerland. Along the thrust the Helvetic nappes were thrust more than 100 km to the north over the external Aarmassif and Infrahelvetic complex. The thrust forms the contac ...

, deformation along the fault has caused the Matt Formation to be overlain by older

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

and

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

-aged marls and

limestones Limestone is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Limestone forms when these ...

of the Blattengrat and Wildflysch nappes.

Paleobiota

The fossil fishes of Glarus were among the earliest known to Western science. Although the slates from Engi mines have been mined since the mid-16th century, the first description of its fossil fishes was by Johann Jakob Scheuchzer in 1705. Scheuchzer's writings prompted a flourishing trade in the fossil fishes of Glarus, which had been sent to museums all around Europe throughout the 18th century. Many of these fishes were described with Linnean taxonomy for the first time in the early 19th century by Europe's pioneering paleontologists, including

Henri Marie Ducrotay de Blainville Henri Marie Ducrotay de Blainville (; 12 September 1777 – 1 May 1850) was a French zoologist and anatomist. Life Blainville was born at Arques-la-Bataille, Arques, near Dieppe, Seine-Maritime, Dieppe. As a young man, he went to Paris to study a ...

and

Louis Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he recei ...

. The Glarus slate is consistent with a marine environment in the western Paratethys Sea. The

Alpine orogeny The Alpine orogeny, sometimes referred to as the Alpide orogeny, is an orogenic phase in the Late Mesozoic and the current Cenozoic which has formed the mountain ranges of the Alpide belt. Cause The Alpine orogeny was caused by the African c ...

uplifted these former marine fossils far above sea level, where they are exposed today. The paleobiota of the Glarus Slate shows close affinities with that of the Rauenberg Lagerstätte of Germany and early Oligocene formations of the

Romanian Carpathians The Romanian Carpathians () are a section of the Carpathian Mountains, within the borders of modern Romania. The Carpathians are a "subsystem" of the Alps-Himalaya System and are further divided into "provinces" and "subprovinces". This is an ...

and the

Caucasus Mountains The Caucasus Mountains * * Azerbaijani: , * * * * * * * * * * * is a mountain range at the intersection of Asia and Europe. Stretching between the Black Sea and the Caspian Sea, they are surrounded by the Caucasus region ...

. All of these localities were formerly part of the Paratethys Sea.

Bony fish

Primarily based on Woodward (1901), with taxonomic changes:

Reptiles

Birds

References

{{reflist Paleogene Switzerland Rupelian Stage Oligocene Series of Europe Glarus thrust Slate formations Paleontology in Switzerland Open marine deposits Geologic formations of Switzerland