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Hampshire Museums Service

Cretaceous

This geological period began with the Berriasian stage approximately 145.6 million years ago and concluded with the Maastrichtian stage approximately 65.0 million years ago. Other stages are recorded elsewhere in Europe but are not present here.

The terrestrial deposits of the Barremian stage represent the early part of the Cretaceous period of Hampshire and the Isle of Wight. The marine transgression which followed is represented by the remaining seven stages, of which the Campanian is the most recent stage found in Hampshire. These Cretaceous stages have been divided into ten formations of marl, clay, sand, sandstone and limestone. Each formation contains a diverse fossil fauna dominated by vertebrates in the early stages giving way to mollusca in the later stages.

The Cretaceous lasted about 80 million years and in Hampshire is approximately 1,000 metres thick. The majority of the down-land in Hampshire and the Isle of Wight over 100 metres high overlies the chalk of the Late Cretaceous Period.

Senonian Stage

The Senonian stage was deposited between 88.5 and 65.0 million years ago. In Hampshire and the Isle of Wight the Senonian is represented by approximately 400 metres of soft limestone/chalk and subordinate marls which are thought to have been deposited at the bottom of an extensive, 100m deep, sea. The Senonian is the collective term for the uppermost Cretaceous chalk which includes the Coniacian, Santonian, Campanian and Maastrichtian stages. The Maastrichtian is not represented in Hampshire. Senonian chalk is present below the higher downland and in the sea cliffs at each end of the Isle of Wight. The stage is also present in Portsdown Hill and below most of the higher parts of the Hampshire downland. Elsewhere it is concealed by younger sediments.

We have comprehensive collections of fossils and geological specimens, particularly from the Fareham and Winchester areas of Hampshire. The fossil fauna from this stage is dominated by invertebrates, particularly echinoids. Vertebrates, mainly shark teeth, are also well represented in the collection.

Turonian Stage

The Turonian stage was deposited between 90.4 and 88.5 million years ago. In Hampshire and the Isle of Wight the Turonian stage is represented by approximately 59 metres of soft limestone/chalk and subordinate marls. These sediments are thought to have been deposited at the bottom of an extensive, 100 metre deep, sea. The Turonian stage, formerly referred to as the Middle chalk, is now included in the White Chalk formation. The Turonian stage is present below the higher downland and in the sea cliffs each end of the Isle of Wight. It is also present below most of the higher parts of the Hampshire downland and at various depths throughout the rest of the county.

We have comprehensive collections of fossils and geological specimens, particularly from the Winchester area. The fossil fauna from this stage is dominated by invertebrates, particularly brachiopods and echinoids. Vertebrates are poorly represented in the collection.

Cenomanian Stage

The Cenomanian stage was deposited between 97.0 and 90.4 million years ago. In Hampshire and the Isle of Wight the Cenomanian stage is represented by approximately 64 metres of soft limestone/chalk and marls formed by sediments deposited at the bottom of an extensive, 100m deep, sea. The Cenomanian stage was formerly known as the Lower Chalk but is now usually referred to as the Lower Chalk formation. Cenomanian chalk is present below the higher downland and in the sea cliffs at each end of the Isle of Wight. With the exception of the Alton area, this stage is deeply buried below most of Hampshire's downland and is concealed by younger geological periods throughout the rest of the county.

Fossils and geological specimens from this stage are poorly represented in the collection.

Albian Stage

The Albian stage was deposited between 112.0 and 97.0 million years ago. In Hampshire and the Isle of Wight the Albian stage is represented by approximately 71 metres of clays and greensands which derive from wholly marine sediments deposited in water between 27 and 54 metres deep. In the past, the Albian stage was also known as the Selbornian which includes the Gault and Upper Greensand. The Albian stage is present below the southern part and in the sea cliffs at each end of the Isle of Wight. The stage is concealed below more recent geological periods in Hampshire and is only present at the surface southeast of Alton.

We have few fossils and geological specimens from this stage in the collection, various rare zonal cephalopods and bivalves are the best represented.

Aptian Stage

The Aptian stage was deposited between 124.5 and 112.0 million years ago. In Hampshire and the Isle of Wight the Aptian stage is represented by approximately 213 metres of clays and greensands. The Aptian stage (formerly the Lower Greensand) is now divided into the Lower and Upper Aptian stages. These stages include the Atherfield Clay and Ferruginous Sand formations which are represented by marine sediments of various depths beginning with the marine transgression which marked the close of the Barremian stage. The Aptian stage is present below the southern part and in the sea cliffs at each end of the Isle of Wight, particularly in Chale Bay. In Hampshire the upper part of this stage is present near Petersfield, but is concealed elsewhere in the county by more recent geological periods.

Our collections of fossils and geological specimens from this stage are restricted to the various outcrops on the southern side of the Isle of Wight. Invertebrate fossils from the Atherfield area of Chale Bay are well represented in the collection.

Berremian Stage

The Berremian stage was deposited between 131.8 and 124.5 million years ago. In Hampshire and the Isle of Wight the Berremian Stage is represented by approximately 228 metres of marl or variegated clays, limestones, sand, sandstone and black shale. The Berremian Stage (formerly the Wealden Marl and Wealden Shales) is divided into the Wessex and Vectis formations. The lower part or Wessex formation is represented by sediments from swamps, muddy lagoons and drainage systems serving an extensive low-lying basin. The overlying Vectis formation is represented by sediments, thought to have been deposited in an estuary, which became choked with deltaic deposits.The Berremian stage is concealed below the southern part of the Isle of Wight and outcrops in Compton, Brighstone and Sandown Bays. This stage is either absent or concealed below more recent geological periods and is not present at the surface anywhere in Hampshire.

Our collections of fossils and geological specimens are restricted to the various outcrops on the southern side of the Isle of Wight. Vertebrates, particularly reptiles, collected between Compton and Chale Bay are well represented in the collection.

Other Geological Periods

Specimens from other geological periods include numerous rock, mineral and fossils from the British Isles, most collected more than 100 years ago. Well-known geological periods from outside Hampshire include the Cretaceous, Jurassic, Carboniferous, Devonian and Silurian. Particularly noteworthy collections include: molluscs from the Cretaceous, Greensand of Devon; Cephalopods from the Jurassic of Dorset and Yorkshire; plants from the Carboniferous of the Midlands; and sectioned corals from the Devonian and Silurian of the West Midlands. These specimens tend to be poorly provenanced and for this reason considered to be less important than the main Hampshire collection but are retained for teaching and display purposes.

 

Cretaceous vertebrates

Vertebrates remains are not common in the Cretaceous sediments of Hampshire. Fossil fish remains, particularly individual teeth of sharks and rays, are the most frequently found of the marine vertebrate fossils. Disarticulated remains of fossil reptiles, including dinosaurs, dominate terrestrial vertebrate faunas.

Cretaceous invertebrates

Invertebrates remains are common in the Cretaceous sediments of Hampshire. Fossil mollusc remains dominate the marine and freshwater faunas. Marine arthropods, corals, echinoids, molluscs and sponges are particularly well represented in the collection but we have few terrestrial invertebrates.

Vertebra
Vertebra Iguanodon

Asteroid Metopaster
Asteroid Metopaster

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