The

Palaeozoic

Era.

Permian

Amphibians, such as Eryops, which reached a length of 1.5 metres (5 feet), and the pond dweller Diplocaulus, remain successful during the Permian period. However, the reptiles become the dominant land fauna, such as Dimetrodon which is a common carnivorous reptile. It reached a length of 3.5 metres (11 feet). The first mammal-like reptiles appeared during this period.

At the end of the Permian period, 248 million years ago, many groups of animals including the Goniatites and Trilobites become extinct.

The name Permian is derived from the Perm province in the Ural Mountains, where rocks of this age are extensively developed.

Dimetrodon

Eryops

Diplocaulus

Upper
Carboniferous

(Pennsylvanian)

The Pennsylvanian period is the division used in North America which corresponds with the Upper Carboniferous period in Europe. The name Pennsylvanian is derived from the coal measures of the state of Pennsylvania which were formed during this period.

During the latter part of the Carboniferous period forest swamps covered extensive areas of the Northern Hemisphere, and increasingly diverse land plants evolved.
The Carboniferous period is the time during which most of the world's coal deposits were laid down, the coal being formed from compressed layers of rotting vegetation.
These Carboniferous forest swamps were made up of plants which included tree-ferns such as Psaronius, which grew to a height of 15 metres (50 feet), and "scale-trees" such as Lepidodendron, which attained a height of about 30 metres (100 feet).
The first flying insects appeared during the Carboniferous period, and giant dragonflies such as Meganeura, which had a wing span of 70 centimetres (28 inches), inhabited the forest swamps.
Reptiles evolved towards the end of the Carboniferous period, and many types of marine fishes became extinct at the end of this period.

The name Carboniferous derives from the fact that this period contains most of the important coal producing strata.

Psaronius

Lepidodendron

Branchiosaurus

Meganeura

Lower
Carboniferous

(Mississippian)

Crinoids, Corals and Brachiopods all flourished in the seas during this time, the only vertebrate animals are the amphibians and fishes.

Devonian

The evolutionary trends of the Silurian period continued during the Devonian period, with plants and vertebrate animals showing spectacular advances.
Among the invertebrates the Goniatites first make their appearance, along with the first flightless insects.
Both freshwater and marine fishes show a great proliferation of forms, with many heavily armoured fishes including the Pteraspids, and the Cephalaspids such as Hemicyclaspis.
The first amphibians, such as Ichthyostega, appeared towards the end of the Devonian period.

The name Devonian is derived from the county of Devonshire in England, where rocks of this age are extensively developed.

Rhynia

Ichthyostega

Hemicyclaspis

Coelacanth

Dunkleosteus

Bothryolepis

Silurian

No new major groups of invertebrate animals appear during this period.

The "sea scorpions" or Eurypterids, an extinct group of predatory Arthropods, flourished in the seas of the Silurian period, and often reached an enormous size, such as Pterygotus which reached 2.3 metres (7.5 feet) in length.
However, significant developments occur among the vertebrate animals and plants.
Jawless fishes, the Agnathans, begin to diversify towards the middle part of the Silurian period.
The earliest know jawed fishes, the Acanthodians, appear in the Silurian period, along with the first land dwelling plants.

The Silurian period is named after the Silures, an ancient British tribe which inhabited the Welsh Borderland during the Roman times.

Pterygotus

Ordovician

The early fossils from this period show a major evolutionary burst.
Trilobites, Brachiopods and Graptolites form the three major groups of animal fossils from this period. Bivalves, and later the Nautiloids, begin to rapidly diversify during the Ordovician period.
Corals become more abundant, and Crinoids, Echinoids and Starfish become established.

The Ordovician period is named after the Ordovices, an ancient British tribe who once dwelt in the Welsh Borderland.

Starfish

Crinoids

Cambrian

A great 'explosion' of life occurred in the Cambrian period, with more than 900 species being recorded, compared with the meagre evidence of life in the Precambrian. All of these Cambrian fossils are marine, with the dominant form being the Trilobites.
Brachiopods also appeared, along with Sponges, Bivalves, Gastropods, worms, jellyfish, early 'experimental' Echinoderms, and Arthropods including Crustaceans.
By the middle of the Cambrian period Graptolites appeared, along with Corals and Nautiloids.
Plant life is essentially limited to Algae.

The name Cambrian is derived from Cambria, the ancient Roman name for Wales, where rocks from this period were first studied.

Nautiloids

Bivalves

Sponges

Trilobites

Algae

Jellyfish