GCR block - Mesozoic - Tertiary Fish/Amphibia (MZ-TR-FI-A)

Mesozoic - Tertiary Fish/Amphibia

Block Description

UK map showing distribution of GCR sites of GCR block MZ-TR-FI-A
Distribution of GCR sites of GCR block Mesozoic - Tertiary Fish/Amphibia

In contrast to the manner in which most invertebrate fossils are represented in the GCR, fossils of vertebrates, arthropods (except trilobites) and terrestrial plants do have their own dedicated GCR Blocks, because of the relative rarity of the fossil material. The GCR sites selected for the Mesozoic-Tertiary Fish/’Amphibia’ GCR Block represent the British fossil record of fishes and stem Tetrapoda and Amphibia of the Mesozoic Era and Tertiary sub-Era (the first part of the Cainozoic Era), from about 250 million years ago (Ma) to 2 Ma. At the end of the Permian Period (= end of Palaeozoic Era, preceding the Mesozoiz Era) a significant, global, mass extinction took place, enabling this ‘unit’ of the fossil record to have a distinct opening signature (the total demise of all the older groups of agnathans); the end of the Tertiary sub-Era marks the beginning of the ‘Great Ice Age’.

Palaeontological characteristics

The term ‘fishes’, unlike ‘mammals’ or ‘birds’ includes a range for aquatic vertebrates across several taxonomic classes. It refers to the living bony fishes (the teleosts) and cartilaginous sharks, rays and skates (the chondrichthyans), as well as a number of surviving representatives of older groups that were much more common in the past, such as the coelacanths, dipnoans (lungfishes), myxinoids (hagfishes) and petromyzontids (lampreys). The hagfishes and lampreys are jawless (agnathan) fishes. There are also two other groups of ‘fish-like’ aquatic chordates, which are not strictly ‘fishes’. These are the living lancelets (cephalochordates) and the extinct conodonts, which are both important for understanding fish evolution and are considered within this GCR Block.

Following the appearance of fishes in Ordovician-Silurian times, when the group were entirely marine, non-marine environments are represented in British Devonian rocks. The Devonian Period had been unmistakably an ‘Age of Fishes’ with its proliferation of species in the marine realm and the entry into fresh waters on all continents. An end-Devonian mass-extinction event involved the total demise of all the older groups of agnathans. Only the myxinoids (hagfishes), lampreys and most of the gnathostomes survived. The disappearance of so many vertebrate types made way for the gnathostomes, in particular, to radiate and expand the group.

The end-Permian mass-extinction event led to a burst of evolution and diversification in the Cainozoic Era comparable to the Devonian radiation.

As well as displaying the evolution of fossil fishes during Mesozoic and Tertiary time, Britain continues to yield invaluable material that helps eluidicate the evolution of tetrapods; the localities yielding important ‘Amphibia’ material are few in number, but are also globally rare.

Palaeoenvironment and palaeogeography

The different depositional environments that developed in Britain during late Palaeozoic times are summarised on the following pages:


GCR site selection

For the purposes of site evaluation and selection, the GCR sites can be grouped into three principal themes or ‘networks’:

• British Triassic fossil fishes

• British Jurassic fossil fishes

• British Cretaceous fossil fishes

• British Cainozoic fossil fishes

• British Mesozoic-Tertiary stem Tetrapoda and Amphibia

Within the overall rationale of the GCR, sites were assesed with the following weightings in mind:

• sites of international significance because they have yielded fossils that are the ‘type’ material.

• sites where the fossils are exceptionally well preserved, showing features not seen elsewhere

• best-available sites for major fish/early tetrapod–amphibia assemblages necessary to represent evolutionary succession

• sites with particular significance to science and history of palaeontology in the development of studies of early vertebrates

• sites enabling the interpretation of the environments in which the animals lived.

Volume Introduction

Mesozoic - Tertiary Fish/Amphibia

Site List

Your selection found 24 GCR sites. Sites are sorted alphabetically by country, local authority and then by site name -
CodeNameCountryLocal AuthorityGrid RefGCR Site Account
2984Totternhoe (Chalk Quarry)EnglandBedfordshire CCSP982222Site Account
2948Boxford Chalk PitEnglandBerkshireSU431719Site Account
2952Lyme Regis coast (Pinhay Bay to Charmouth)EnglandDevon CCSY327909Site Account
3143SidmouthEnglandDevon CCSY092838Not available
2910Barton CliffEnglandDorset CCSZ218930Site Account
2900Durlston BayEnglandDorset CCSZ035772Site Account
2901Watton CliffEnglandDorset CCSY451908Site Account
2912Southerham (Lime Kiln Quarries)EnglandEast Sussex CCTQ426096Site Account
2915Southerham Grey PitEnglandEast Sussex CCTQ427090Site Account
2914Burnham-on-CrouchEnglandEssex CCTQ921967Site Account
2913MaylandseaEnglandEssex CCTL908035Site Account
2908Blockley Station QuarryEnglandGloucestershireSP181370Site Account
2898Lee-on-SolentEnglandHampshire CCSU552014Site Account
2909King's QuayEnglandIsle of WightSZ538941Site Account
2906Blue Bell Hill PitsEnglandKent CCTQ736614Site Account
2911Herne BayEnglandKent CCTR217691Site Account
3008Pegwell BayEnglandKent CCTR348640Not available
2907SheppeyEnglandKent CCTQ955738Site Account
2902UpnorEnglandMedwayTQ757712Site Account
2903Abbey WoodEnglandOuter London - East and North EastTQ480786Site Account
2899Kirtlington Old Cement Works QuarryEnglandOxfordshireSP494199Site Account
2949Windsor HillEnglandSomersetST614451Not available
2904Bognor RegisEnglandWest SussexSZ920979Site Account
2905Bracklesham BayEnglandWest SussexSZ823951Site Account
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