u/WaitItsAllOhio

Bringing some love from Ohio! On the north side of Kelleys Island is Glacial Grooves State Park. The Wisconsin glacier carved a set of grooves into the exposed Columbus Limestone here that are the largest accessible glacial striations on Earth. The current grooves measure approximately 430 feet long, 35 feet wide, and 15 feet deep. Bit hard to get to since you need to take a ferry, but it's a great feature of our state!

If you want a deeper dive on them (cause this is/r/geology, after all):

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Four hundred million years ago, give or take, this was the floor of a shallow Devonian sea. Silty carbonate ooze accumulated on the seafloor, and over the subsequent eons it lithified into Columbus Limestone: a high-calcium, thin-bedded, much-jointed formation that would eventually become the backbone of the Lake Erie island chain.

The limestone sat there for roughly 399,982,000 years. Then the Laurentide Ice Sheet showed up. At the peak of the Late Wisconsin glaciation, around 18,000 years BP, Kelleys Island was underneath approximately one mile of ice. The island sits on the east flank of the Cincinnati Anticline, part of a cuesta ridge that runs north through the Lake Erie Archipelago; the Columbus Limestone and the underlying Monroe Formation of the Upper Silurian are what give the islands their structure.

The formation mechanism is still debated. Traditional models attribute the grooves to gravel and cobbles embedded in the base of the ice sheet scraping along the bedrock under immense pressure. More recent work from ODNR suggests the grooves may have been carved by sand-charged meltwater flowing at extreme velocity and pressure through subglacial channels. Either way, the bedrock lost the argument.

The grooves are oriented in the direction of glacial movement, and you can read the ice's trajectory in them. Morrison's 1950 economic geography of the island noted that Sweet Valley, the low central depression running east-west through the island's interior, was itself the product of ice scour. Everywhere you look on Kelleys Island, the landscape is a palimpsest of glacial violence. You've got striated pavement on the east shore, enormous erratics scattered across Long Point, and the grooves themselves, running north to south as the world's most aggressive geological drag marks.

Before someone mentions, yes, similar (smaller) grooves exist on Gibraltar Island and West Sister Island (both in Lake Erie, so not THAT Gibraltar). The grooves were designated a National Natural Landmark in 1967 and have been a State Memorial since 1923.

The grooves used to be longer. Considerably longer. They originally extended from their current position north into Lake Erie; the feature was, by historical accounts, vastly more impressive than what survives today. The reason it does not survive is that the Kelley Island Lime and Transport Company, along with earlier operations dating back to 1833, quarried the Columbus Limestone for flux stone, building material, and lime. The Great Lakes stone trade literally started on Kelleys Island; John A. Clemons opened the first quarry and built a dock on the north shore in 1833, and by 1867 the island was shipping 60,852 tons of stone annually. By 1912, the company operated three quarries covering huge swaths of the island, employed 400 men, and shipped 546,922 tons in 459 boat loads. The calcium carbonate content of the upper twenty feet of quarried stone ran between 85 and 98 percent. It was excellent flux. It went to blast furnaces in Buffalo, Cleveland, and Gary, and to lime kilns in Duluth.

The quarry company eventually owned about 1,000 acres of the island's 2,888 total area. They quarried away the island's higher elevations entirely. Morrison noted that the area above 620 feet had been "largely quarried away" by his visitation in 1950. The company quarried through the glacial grooves without hesitation.

The quarry closed in 1941. Not because anyone had a crisis of geological conscience; the equipment was old, the docking facilities were inadequate, and the company could supply demand more cheaply from its operations at Marblehead on the mainland. What survives of the grooves today is, essentially, whatever the quarrymen couldn't reach or didn't bother with before the economics stopped making sense.

The grooves are now behind a fence on a boardwalk, maintained by the ODNR. Visitors look down into them from above. They are genuinely spectacular, even in their reduced state. It's fifteen feet of polished, striated Devonian limestone, the scratch marks of a continent-sized ice sheet still legible after eighteen millennia. Fossils from the Columbus Limestone's original marine environment are visible in the groove walls. You can stand on an Ordovician-to-Devonian carbonate platform, look at the gouges left by Pleistocene ice, and contemplate the fact that the most destructive force to visit this particular piece of rock was not a mile-thick glacier but a limestone company from Cleveland.

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Thinking of them today since Kelley's Island is currently seeing its record flooding.

(If you go: Kelleys Island Ferry from Marblehead, grooves are free to visit. Inscription Rock, a flat-topped limestone boulder on the south shore covered in Native American petroglyphs, is nearby and worth the walk. Bring sunscreen; the island is flat, treeless in spots, and the lake breeze is a liar.)

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Works Cited

Bolsenga, Stanley J. and Charles E. Herdendorf, eds. Lake Erie and Lake St. Clair Handbook (Wayne State University Press, 1993).

Forsyth, Jane L. Dating Ohio's Glaciers. Ohio Division of Geological Survey, Information Circular No. 30 (1961).

Forsyth, Jane L. "Geology's Contribution to Ohio's Landscapes." The American Biology Teacher 27, no. 5 (May 1965): 358-362.

Kesler, Stephen E. Great Lakes Rocks: 4 Billion Years of Geologic History in the Great Lakes Region (University of Michigan Press, 2019).

Morrison, Paul Cross. "Kelleys Island, Ohio: An Economy in Transition." Economic Geography 26, no. 2 (April 1950): 105-124.

Photo Credit: Kelly's Island official website.

Ohio historian here that thought it'd be fun to share some fun anecdotes from the field that are, well, very Ohio. To be clear, yes, I am an actual Ohio historian. Yes, this is an actual story, not satire. I cannot confirm or deny that I know or have met these people. Sometimes, paleontologists are just really fucking dedicated to the craft. And odd. Definitely odd.
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Daniel Fisher, a paleontologist from the University of Michigan, had been excavating mastodon bones across the Great Lakes for a decade, and the same pattern kept showing up. The butchered remains always sat at the bottom of ancient ponds. They weren't scattered by scavengers or washed in by floods. They were organized into 150-to-200-pound sections, with vertical wooden posts driven into the pond bed alongside them, as if somebody planned to come back. At one site near Jackson, Michigan, Fisher found watermelon-sized masses of sand and gravel wrapped in mastodon intestine: anchors, designed to hold the meat on the bottom. Inside the intestine casings, he isolated eleven-thousand-year-old bacteria, still alive, from the gut of an extinct species.

Obviously, things could live for far longer at the bottom of bogs than previously suspected. His hypothesis was that Paleoindians were using ponds as walk-in freezers.

He started testing with legs of lamb from a butcher shop, submerged in a shallow pond at the University of Michigan's E.S. George Reserve near Hell, Michigan. (yes, the town is actually called Hell.) He left them down there for months, fished them out, and sent samples to a commercial laboratory. The lab results came back cleaner than heexpected. There was fewer bacteria in the pond-stored lamb than in a control sample from Fisher's home freezer!

But a seven-pound leg of lamb is not a mastodon. He needed to scale it up.

On February 13, 1993, a twenty-eight-year-old draft horse weighing fifteen hundred pounds died of natural causes on a colleague's farm near Chelsea. Fisher and two colleagues butchered it using stone tools he'd knapped himself, replicating the techniques he'd documented at mastodon excavation sites. For skinning, he noted, the stone tools worked better than steel knives (fuck you, Iron Age elitists). They carved the carcass into slabs weighing between fifty and a hundred and fifty pounds, fashioned anchors from sections of horse intestine stuffed with gravel from the pond margin, and sank the whole operation through a hole chopped in the February ice.

The meat stayed fresh through the winter. By late spring, some sections had bloated with gas and bobbed to the surface. Fisher thought the experiment had failed.

It hadn't. Actually, quite the opposite. Lactobacilli, the same bacteria used to make cheese and yogurt, had colonized the horse meat and was pumping out carbon dioxide. The CO2 made the tissue uninhabitable for the spoilage microbes that would otherwise have decomposed it. The horse hadn't rotted. It had fermented. Fisher described the result as "a very tender, quite pungent, cheesy-smelling and -tasting material" that was "still quite palatable."

He kept pulling out sections every two weeks, cooking them over an open fire, and eating them through late June. He presented the results that May at the Society for American Archaeology meeting in Minneapolis. The paper went into Current Research on the Pleistocene.

Bradley Lepper, then curator of archaeology at the Ohio Historical Society, told the Chronicle of Higher Education he'd been "dragged kicking and screaming" to accept Fisher's hypothesis. But the results were hard to argue with. The technique preserved meat for at least six months, outperformed a modern freezer by bacterial count, and the only technology it required was a pond, some intestine, and a handful of gravel. Paleoindians had all three.

Oh, and then Brad found his own 10,000 year old bacteria in his own mastodon in his own comedic story about bog caching. But I'll save that for the next thread!

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Works Cited (if you're a sick fuck and want to actually read this stuff)

Fisher, Daniel C. "Taphonomic Analysis of Late Pleistocene Mastodon Occurrences: Evidence of Butchery by North American Paleo-Indians." Paleobiology 10, no. 3 (Summer 1984): 338–57.

Fisher, Daniel C. "Paleobiology and Extinction of Proboscideans in the Great Lakes Region of North America." In American Megafaunal Extinctions at the End of the Pleistocene, edited by Gary Haynes, 55–93. Dordrecht: Springer, 2009.

McDonald, Kim A. "Early Man's Refrigerator." The Chronicle of Higher Education, May 12, 1995.

University of Michigan News. "Underwater Storage Techniques Used by Early North American Hunters Preserve Meat for at Least Six Months." Press release, May 3, 1995.

Martin, Aaron, and Kelly House. "U-M's Mastodon Man Calls It a Career After Decades of Solving Ice Age Mysteries." Bridge Michigan, November 23, 2023.

Glacial Grooves State Park on Kelley's Island, OH. The best place on Earth to see glacial striations.

Field Notes from Ohio: When a paleontologist turned horse meat into cheese and ate it to prove his theory right.