Smithsonian National Museum of Natural History Geologic Time The Story of a Changing Earth
Presented by the Department of Paleobiology.
The Silurian
Contents
Overview
Silurian Marine Life
The Invasion of Land
Geology and Climate
Evidence
Model of Cooksonia
learn more
sample
Tabulate coral
Eurypterid
Silurian diorama
references and links
Foundational Concepts
Dating Methods
Earth Processes
Life Processes
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Glossary Credits Email Us


OVERVIEW
Silurian 444 - 416 mya
Defining Characteristics:
  • • distinct estuarine, freshwater, and terrestrial ecosystems develop—the start of significant life on dry land

  • • Map of the Silurian World
Secondary Characteristics:
  • • first vascular plant fossils
  • • wide and rapid spread of jawless fishes
  • • first extensive coral reefs

The Silurian System was named in the 1830s by English geologist Sir Roderick Impey Murchison. Murchison had been studying the fossil-bearing rocks in southern Wales, and he noticed that they appeared to be distinct from both the older (lower) rocks that formed the Cambrian and the younger (higher) rocks of the Devonian. He gave this geological stage the name Silurian after the Silures, an ancient Celtic tribe that lived along what is now the Welsh-English border.

The Silurian physical world was vastly different in many ways from the world of today. For example, the equator passed through what is now North America, and a nearly continuous inland sea extended from New York to Nevada. Life was also quite different. Following the end-Ordovician extinction event, Silurian marine faunas rebounded in the warm, shallow continental seas. Large coral reefs made their first appearance during this time. Although marine life was diverse and abundant, there were only a few types of small plants and terrestrial arthropods on land in the Silurian. However, these represent the first true terrestrial ecosystems on Earth and include the first fossil records of vascular plants. These terrestrial ecosystems became more complex, especially during the Late Silurian, as upright plants evolved and populated the wet parts of lowland landscapes.




Overview | Silurian Marine Life | The Invasion of Land
Geology and Climate



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