The Maastricht Formation (Dutch

Dutch language

Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...

: Formatie van Maastricht; abbreviation: MMa), named after the city of Maastricht

Maastricht

Maastricht is situated on both sides of the Meuse river in the south-eastern part of the Netherlands, on the Belgian border and near the German border...

, the Netherlands

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, is a geological formation in the Netherlands and Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 whose strata date back to the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

, within 500k years of the K-Pg boundary, dated to 65.5 million years ago. The formation is part of the Chalk Group and is between 30 and 90 metres thick. It crops out

Outcrop

An outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. -Features:Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by a mantle of soil and vegetation and cannot be...

 in southern parts of Dutch

Limburg (Netherlands)

Limburg is the southernmost of the twelve provinces of the Netherlands. It is located in the southeastern part of the country and bordered by the province of Gelderland to the north, Germany to the east, Belgium to the south and part of the west, andthe Dutch province of North Brabant partly to...

 and Belgian Limburg

Limburg (Belgium)

Limburg is the easternmost province of modern Flanders, which is one of the three main political and cultural sub-divisions of modern Belgium. It is located west of the river Meuse . It borders on the Dutch provinces of North Brabant and Limburg and the Belgian provinces of Liège, Flemish Brabant...

 and adjacent areas in Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

. It can be found in the subsurface

Subsurface

Subsurface is the seventh studio album by British progressive metal band Threshold. The album was released in August 2004, and received an Album of the Month award in several European music magazines....

 of northern Belgium and southeastern Netherlands, especially in the Campine Basin and Roer Valley Graben. Dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

 remains are among the fossils that have been recovered from the formation.

Lithology

The Maastricht Formation consists of soft, sand

Sand

Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

y shallow marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 limestone

Limestone

Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 (in Limburg locally called "mergel"), in fact chalk

Chalk

Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....

 and calcareous arenite

Arenite

Arenite is a sedimentary clastic rock with sand grain size between 0.0625 mm and 2 mm and contain less than 15% matrix. The related adjective is arenaceous...

. These lithologies locally alternate with thin bands of marl

Marl

Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and aragonite. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay...

 or clay

Clay

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

. The lower parts of the formation contain flint

Flint

Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...

 concretion

Concretion

A concretion is a volume of sedimentary rock in which a mineral cement fills the porosity . Concretions are often ovoid or spherical in shape, although irregular shapes also occur. The word 'concretion' is derived from the Latin con meaning 'together' and crescere meaning 'to grow'...

s. The upper parts can have shell

Exoskeleton

An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...

rich layers. Its age is between about 70 and 66 million years, which puts it in the Maastrichtian

Maastrichtian

The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...

, a stage that was named after the formation. The top of the formation can possibly be Danian

Danian

The Danian is the oldest age or lowermost stage of the Paleocene epoch or series, the Paleogene period or system and the Cenozoic era or erathem. The beginning of the Danian age is at the Cretaceous-Tertiary extinction event...

 (early Paleocene

Paleocene

The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

) in age.

The type locality

Type locality (geology)

Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....

 is at the ruins of Lichtenberg castle on the Sint-Pietersberg, Maastricht.

Stratigraphy

The Maastricht Formation was first described by Belgian geologist André Dumont

André Dumont

André Hubert Dumont was a Belgian geologist.Dumont was born in Liège. His first work was a masterly Mémoire on the geology of the province of Liège published in 1832. A few years later he became a professor of mineralogy and geology and afterwards Rector of the University of Liège...

 in 1849. The formation is subdivided in seven members, from top to bottom these are the Meerssen Member, Nekum Member, Emael Member, Schiepersberg Member, Gronsveld Member, Valkenburg Member and Kunrade Member. The members are often hard to distinguish.

The Maastricht Formation is overlain by the Paleocene Houthem Formation

Houthem Formation

The Houthem Formation, named after the Dutch town of Houthem, is a geological formation that crops out in the south of Belgian and Dutch Limburg. It has also been found in borings in the northeastern part of the Campine Basin...

 and was deposited on top of the older Gulpen Formation.

Dinosaurs

Dinosaur Dinosaur Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of... s reported from the Maastricht Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Betasuchus Betasuchus Betasuchus was a theropod dinosaur which lived during the Late Cretaceous Period.Its fossil, holotype BMNH 42997 , a part of a right femur, 312 mm long, was found in The Netherlands near Maastricht, and originally described as a new species of Megalosaurus in 1883 by Harry Seeley: M...	B. bredai	Geographically present in the Dutch province of Limburg.		"Femur."	An Abelisauroid.
Indeterminate euhadrosaurian remains		Geographically present in the Dutch province of Limburg.
Megalosaurus Megalosaurus Megalosaurus is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period of Europe...	M. bredai	Geographically present in the Dutch province of Limburg.			Reclassified as Betasuchus bredai.
Orthomerus Orthomerus Orthomerus is a genus of duckbill dinosaur from the Late Cretaceous of The Netherlands, Belgium and possibly Ukraine. It is today an obscure genus, but in the past was conflated with the much better known Telmatosaurus.... .	O. dolloi.	Geographically present in the Dutch and Belgian provinces of Limburg.			A dubious Hadrosaurid Hadrosaurid Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper... .
"Unnamed ornithurine "	Unnamed				A primitive ornithurine
"Unnamed ornithurine "	Unnamed				An ornithurine
"Unnamed enantiornithine"	Unnamed				An enantiornithine

Mammals

Mammal Mammal Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young... s reported from the Maastricht Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Maastrichtidelphys	M. meurismeti	Geographically present in the Dutch province of Limburg.		"Right upper molar."	A Herpetotheriid Marsupial Marsupial Marsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central... .

Mosasaurs

Mosasaur Mosasaur Mosasaurs are large extinct marine lizards. The first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764... s reported from the Maastricht Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Carinodens Carinodens Carinodens is a genus of mosasaur. It was named in 1969 as a replacement for Compressidens, which was already in use for a mollusk. Measuring approximately in length, it is one of the smallest known mosasaurs. It is widely considered a sister taxon to Globidens. It also had round, blunt teeth for...	C. belgicus
	C. fraasi				Junior synonym of C. belgicus.
Globidens Globidens Globidens is an extinct genus of mosasaur lizard.Globidens alabamaensis was first described by Gilmore . A second species was described by Russell . The third North American species Globidens ("Globe teeth") is an extinct genus of mosasaur lizard.Globidens alabamaensis was first described by...	G. fraasi				Reclassified as Carinodens fraasi
Liodon Liodon Liodon is a genus of mosasaur from the Late Cretaceous. Remains assigned to this genus have been found in Africa, Asia, Europe, America and South America, and New Zealand. It was first named by Richard Owen as Leiodon, but that name was already in use for a fish, necessitating the name...	L. sectorius
Mosasaurus Mosasaurus Mosasaurus is a genus of mosasaur, carnivorous, aquatic lizards, somewhat resembling flippered crocodiles, with elongated heavy jaws. The genus existed during the Maastrichtian age of the Cretaceous period , around 70-65 millions years ago in the area of modern Western Europe and North America...	M. hoffmanni
	M. lemonnieri
Plioplatecarpus Plioplatecarpus Plioplatecarpus is a genus of mosasaur lizard. Like all mosasaurs, it lived in the late Cretaceous period, about 83.5 million years ago.-Description:...	P. marshi