In the heart of the American Midwest, a landlocked state like South Dakota might seem an unlikely place to find remnants of a vast inland sea. Yet, more than 70 million years ago, this very landscape was submerged beneath the Western Interior Seaway, a body of water that stretched across the center of North America, dividing it into two. This ancient sea was not just a geographical feature; it was a thriving ecosystem teeming with life, from giant marine reptiles to sharks and ammonites, the latter of which still shimmer like gemstones in the Smithsonian's National Museum of Natural History.
What makes this sea so fascinating is not just its age or the diversity of its inhabitants, but also the fact that it left behind clues that still benefit people today. Over millions of years, the rocks from the seaway broke down and formed fertile soil, which later helped make the American Midwest one of the country's most important farming regions. This is a testament to the enduring impact of ancient environments on our present-day world.
One of the most striking aspects of the fossils found in this sea is their preservation. The ammonite shells, for instance, still shine with colorful patterns due to their composition of nacre, or mother-of-pearl. This material, the same one that gives pearls their shine, became even more visible during fossilization, allowing the shells to reflect light millions of years later. It's a reminder of the intricate beauty that can be preserved through time, even in the most unlikely of places.
The exhibition 'From these lands' at the Smithsonian's National Museum of Natural History showcases hundreds of fossils and artifacts from across the United States, including these shimmering ammonite shells. But what's truly fascinating is the realization that marine fossils are not confined to coastal areas. A sea star fossil from Minnesota, for instance, lived around 457 to 449 million years ago, during a time when warm, shallow seas covered much of the region. This fossil, along with others like it, demonstrates the dynamic nature of Earth's surface, where continents move, sea levels rise and fall, and new rocks form, scattering ancient remnants across the globe.
The discovery of ancient oceans in places like Ohio further underscores the complexity of our planet's history. Rocks beneath Ohio were formed hundreds of millions of years ago, when plants had only just started growing on land. Fossils of brachiopods, clam-like animals that have lived on Earth for more than 500 million years, and crinoids, relatives of today's sea stars, can still be found there. This is a reminder of the deep time scales involved in geological processes and the interconnectedness of life across vast periods of history.
In my opinion, the exhibition 'From these lands' is more than just a display of ancient artifacts; it's a window into the past that helps us understand the present and imagine the future. It invites us to reflect on the enduring impact of ancient environments on our modern world and the dynamic nature of Earth's surface, where the remnants of past seas can be found in the most unexpected of places. It's a testament to the power of nature to shape and reshape our world over millions of years, and a reminder of the importance of preserving and understanding our planet's history for the sake of our future.
