Take a close look at these exquisite Silurian rocks from the state of Maine, USA. (How did I just realize Maine is our only monosyllabic state?) The Silurian, an underappreciated time period, without the cachet of say, the younger Jurassic, is part of the Paleozoic era between the Ordovician and Devonian. Silurian rocks are 443 million years to 416 million years old.
A significant evolutionary milestone during the Silurian was the diversification of jawed and bony fishes.
Life also began to appear on land during the Silurian in the form of moss-like, vascular land plants that grew beside bodies of water. Small terrestrial arthropods also began to appear.
These Maine rocks of the Kittery Formation are old. They show the results of millions of years of deposition, igneous activity, faulting, tectonics, and metamorphism.
However, in researching this week's topic, I discovered the "Silurians," a fictional race of reptile-like humanoids in the long-running British science fiction tv series Doctor Who? Those first Silurians are depicted as prehistoric and scientifically advanced sentient humanoids who predate the evolution of man.