Fossil hunters explore Point Gratiot
By TOM SCHWARTZChautauqua County's natural history was explored and discussed recently through a fossil hunt along the shores of Lake Erie.
Dr. Gordon Baird, a professor at SUNY Fredonia, led fossil hunters to the Point Gratiot beach near the Dunkirk Lighthouse.
Dr Baird told the group about previous trips to this spot. "Many years ago my colleges and I were able to find a well preserved Dunkleosteus (massive prehistoric armored fish) fossil here. This one wasn't very large - only about 12 feet long - but we had to bring it out in five pieces."
When asked which name came first, Dunkirk or the Dunkleosteus, Dr. Baird revealed that the archaic fish, first discovered around this area, was named after geologist David Dunkle.
Trip participants met at the Adams Art Gallery to look at drawings and listen to a lecture by Dr. Baird. "We have zero money at Adams and we were able to have this great program. Think of what we could do if we actually had money," said Marie Tomlinson, fossil hunter and art gallery volunteer.
The two beach spots that were visited both developed into late Devonian bedrock, making the shale and the fossils within it about 370 million years old.
"At this time the Fredonia-Dunkirk area was at about 30 degrees south latitude," said Dr. Baird, "placing this primordial shallow sea somewhere in the southern hemisphere."
At Point Gratiot, a contact point was observed between the Hanover Shale and the Dunkirk Shale where a submarine eroision event pushed up the rock strata.
Dr. Baird showed the dark shale within the Hanover Shale that marks one of the five mass extinctions in the Earth's history.
The next spot on the itinerary was The Corell's Point Pyrite-Goniatite Bed. Within the shale on the beach were countless pyrite nodules for eager fossil hunters to remove with hammers and chisels.
All along the beach spot were fractured concretions commonly called turtle stones. These were formed in ancient marine muds. Some have the appearance of turtle shells because of calcitic water filling in the cracks.
The group brought home a straight cephalopods fossil and an ammonoid fossil (marine invertebrate with a spiral shell like a snail), both casted in pyrite.
Comments on this article may be sent to tschartz@observertoday.com
