Catskill formation

Location: North-central Pennsylvania, USA, along the southern margin of the ancient continent, Euramerica.

Time Period: Late Devonian (specifically, the Famennian age, roughly 375-359 million years ago).

Fauna

  • Early Tetrapods: Animals like Hynerpeton and Densignathus hunted in the shallow waters and would have ventured onto land for short periods.
  • Abundant Fish: Various species of fish, including lobe-finned fish (relatives of tetrapods) and armored placoderms, filled the waterways.
  • Invertebrates: The presence of trigonotarbids (arachnids) and myriapods (like millipedes) indicate a developing terrestrial arthropod ecosystem.

Dominant Vegetation:

  • Archaeopteris Forests: Giant, tree-like progymnosperms called Archaeopteris formed dense forests. These were among the world’s first true trees, reaching heights of up to 60 feet (18 meters).
  • Fern Glades: Rhacophyton, an extensive, shrubby fern, carpeted the forest floor and wetlands.
  • Lycopsid Wetlands: Scale-trees resembling giant club mosses added to the wetland diversity
  • Early Seed Plants: Patches of the earliest seed plants began to appear, taking advantage of disturbed areas such as those created by wildfires.

Landscape:

  • Floodplain environment: the area was part of a vast river system and its floodplains. The landscape was dynamic, with changing river channels, swamps, and areas of occasional fire disturbance.
  • Lush vegetation: Despite periodic disruptions, the environment was predominantly green. Forests and wetlands thrived in this warm and humid climate.

Significance:

Catskill formation offers a remarkably vivid snapshot of a critical moment in Earth’s history:

  • The Rise of Forests: The Archaeopteris forests represented a major step in the evolution of terrestrial plants. These trees created new habitats and profoundly altered the landscape’s structure.
  • Terrestrialization: The fossils of early tetrapods and land-dwelling invertebrates highlight the ongoing transition of life from water to land.