Most of our knowledge about the ancient world is based upon the science of Geology -- the study of rocks.
Because newer layers of sediment are deposited on top of older ones, digging down into the layers is like traveling backward in time.
These rock beds tell stories of flourishing underwater ecosystems, catastrophic ice ages, ash layers from volcanic eruptions, global sandstorms, sandy beaches of long-lost oceans as they grew and shrank over vast expanses of geologic time.
In some cases sedimentation stopped and layers were eroded away. These "discontinuities" make the story harder to read, like a detective novel that has a handful of pages ripped out.
Although geologists can seldom have the opportunity to inspect an entire layer of rock, individual outcroppings can offer glimpses of widespread sedimentary layers that represent "horizons" in time -- snapshots of the Earth from a remote period of the past.
By creating detailed records of these horizons, geologists have created a "Stratigraphic Map" that tells a complete story of time from the Earth's earliest rocks to the present day.
After many years spent studying these layers, geologists have been able to reconstruct the details of an amazing story that reaches hundreds of millions of years into the past -- back to the dawn of life's creation.