Fossil hunting is a common pastime for many people living in upstate New York, and this summer I decided to give it a go.
The recipe for good fossil hunting starts with knowing the land and what kind of rocks make up the layers beneath your feet.
Ancient New York resembled a shallow ocean resting between mountains. These mountains would be pelted with heavy rains, winds, and snow that would slowly chip away at the rocks that coated these mountains. They would fall into the little ocean below and settle on the sea floor where they eventually became sedimentary rocks.
New York has large amounts of shale, a type of sedimentary rock and one of the best for excellent fossil preservation due to limited exposure to harsh conditions and easy burial. Shale is basically compressed mud and clay, making it a cushy resting place that will be resistant to high pressures and heat that could distort or alter fossils.
These rocks were formed roughly 418 million years ago in the Devonian period, a time within the Paleozoic era, and lasted approximately 100 million years. This time period is also known as the Age of Fishes, however, this story centers around the first known arthropods and some of the most abundant and highly diverse organisms of the time, the trilobites.
Taking a brief break from research, I migrated up to Penn Dixie Fossil Park, just south of Buffalo, NY, to begin my search for trilobites.
Penn Dixie is famous for its Devonian fossils and is ranked the #1 fossil park in the U.S. Once a year, they host an event where guests get the exciting opportunity to dig with expert geologists, paleontologists, and other professionals. The experts provide helpful advice, guidance, and a plethora of knowledge, perfect for any beginner fossil hunter.
Trilobites are the most sought after fossil at Penn Dixie. Along with brachiopods, an ancestor to mollusks, trilobites started dying out during the Devonian period, possibly due to changes in sea level and ocean anoxia, or through the impact of a comet. Hence the abundance found as fossils.
What makes these little creatures so cool (besides their resemblance to the Pokemon, Kabuto), is their evolutionary contribution to understanding the Cambrian explosion. This mass-diversification of all life brought about many of the animal species we know and love today thanks to the evolution of vertebrates. Trilobites become monumental in studying this historic event.
Researchers at the Palaeoscience Research Centre in Australia, used trilobites to explore the rate of evolution during the Cambrian explosion. They showed that this time period may be shorter than previously thought. Trilobites went from soft-bodied to hard-shelled in a rapid amount of time, and this was observed all around the world. Fossils of hard-shelled trilobites starting appearing in Spain, China, and Australia, indicating a global evolutionary shift that was stable through the next 20 million years.
I was able to discover a few of my own trilobite fossils at Penn Dixie this summer and will cherish these trail-blazing ancient arthropods for years to come.
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