Earth around 430 million years ago – Silurian
At the time the rocks of the Wren’s Nest were forming, the area was located about the centre of the white circle. Today the Wren’s Nest has a latitude of about 52 degrees north of the equator. Back then around 430-410 million years ago in the time period geologists call the Silurian the Wren’s Nest area was around 30 degrees south of the equator, the latitude today of South Africa, Brazil and Western Australia.
The Wren’s Nest was an environment of shallow warm coral rich seas on the edge of a narrow gulf of much deeper sea, that was the remnant of a once major ocean named Iapetus. In the diagram above just below the white circle, you can make out a landmass with the name Avalonia. Avalonia was the small tectonic plate that included England, Wales, part of Ireland along with some other bits of Europe and Newfoundland. Avalonia was later cut apart when the Atlantic Ocean opened long after the time the rocks of the Wren’s Nest were deposited in the warm Silurian sea.
In this reconstruction of the Earth for the Silurian times, the oceans are blue but the continents are not green. In the Silurian land plants were in an early stage of development, it would seem the land was yet to be clothed in great green forests. A consequence of the absence of extensive plant cover would be rock surfaces being more open to attack from erosion, so there would be more sediment entering the marine environment.