Back in the far ancient past, around 2 billion years ago, a supercontinent called Rodinia is thought to have formed. It started breaking up around 780 million years ago, but the core of it stayed together and in time became the Laurentian Craton. This mass of rock would eventually form the foundation of the continent of North America. Before that, though, it spent some 700 million years wandering around the globe, bumping into other masses of rock, separating from them and moving on. By about 540 million years ago, the Laurentian craton had moved from the southern hemisphere into the vicinity of the equator.
While this movement was occurring, other geological forces and climates were having significant effects on it. Sea level rose, flooding what was then a barren plain. A shallow sea formed, and the exposed rock around the sea weathered and eroded. The resulting sand washed into the ocean and built sand beds which in time would compress into sandstone. The ocean withdrew after several million years as climate changed. When it warmed up again, some 20 million years later, another series of shallow seas flooded the land. By this time, a whole ecosystem of plants and animals had evolved in and around the seas.
By about 440 million years ago, life thrived in Earth’s oceans. Trilobites, (ancient arthropods), bivalves, coral and brachiopods had evolved over millions of years. And then, the first of five large mass extinctions occurred, killing off some 70% of the life forms existent on earth. All that was left of the once-thriving Corals, trilobites, brachiopods and bivalves were fossilized shells compressed into ancient limestone. With the coast cleared, the life that survived went about adapting to the new environments and filling the ecological niches left by these ancestors. Plants including mosses moved onto the land and thrived there, impacting the climate at the same time. Ancestral boney fishes and new versions of marine invertebrates like trilobites and plankton reoccupied the sea. New versions of corals went back to building reefs. And then, after building this new world for about 75 million years, the second mass extinction occurred, making room for the next round of life building.
Temperatures rose, and the shallow seas covering Owl Acres expanded and contracted, leaving layers of gypsum, rock salt and other minerals as well as evolutionary fossil records of life in those seas. On land, swamps were left behind by the receding oceans, supporting scale trees and tree ferns which would become the coal beds beneath Owl Acres. vascular plants evolved into trees and forests. Reptiles and amphibians moved onto the land, and fish exploded in the seas. All this activity built up to another mass extinction, known as The Great Dying. This time, 95% or more of all sea life was killed, including all of the trilobites. 70% of life on land was also destroyed. The causes of this extinction, like the last two, are unclear, but it made room for new types of life, including large amphibians and the ancestors of crocodiles and dinosaurs. The next mass extinction, about 50 million years later, killed off about a third of the marine species and many of the land-based species as well.
This made room for yet another explosion of life including the dinosaurs, myriad species of insects, fishes, and small mammals. Ammonites, a family of sea mollusk and one of the most diverse families of animals on the planet, left huge deposits of limestone in the sea beds. Life was thriving in grand variety when, one day, a meteor struck the earth near the Yucatan. What had been an ordinary day turned into a hellscape as molten rock from the impact rained down, setting the forests on fire. Toxic gasses filled the air, and the dust from the impact blotted out the sun. Impact winter had arrived. Or maybe it was volcanic activity from within the earth. Whatever it was, species ranging from ammonites to nonavian dinosaurs were gone. In fact, 75% of all species were once again wiped out. The world as we know it began to take shape. In time, the dominant species would be humans.
Layer upon layer of this history is compressed into the sandstone and limestone bedrock beneath Owl Acres. Some of these ancient records have surfaced within the state, but Owl Acres keeps its secrets hidden below yet more layers of its history.