I was feeling pretty cocky and confident about the difference between shale and slate yesterday when Bethany posted the previous rock photos, but then I felt doubtful. What is the difference? I was near 90% sure the flat black rocks we’ve been playing with all our lives (stone skipping contests, decorating sand castles, diving for rocks), were, in fact, slate, but had to research it to find out for sure. Here’s what I found on Wiki Answers (and they have all the answers!):
"Slate is a metamorphic rock whose parent rock is Shale. Slate is composed of microcrystals, and because of its degree of foliation, it cleaves easily into thin sheets or plates. Shale is a sedimentary rock. It can cleave, also. The easiest way to to tell the difference between the two is to smell the rock when it is wet. Shales smell like clay, slates do not."
And then, not two entries below in the list of Google search results (Wiki Answers are first?), I found a very interesting blog called: “Lake Trek: A Thousand Mile Walk on the Beach” kept by writer/adventurer Loreen Niewenhuis from Battle Creek. Fascinating! Loreen walked the whole shoreline of Lake Michigan and wrote about her progress in her blog, along with posting tons of photos and video clips. She finished her walk last September at Chicago’s Navy Pier, but continues to write about her work in progress (a book based on her 1000 mile walk along the beach), highlights and memories from last year’s walk, and even this summer’s re-visits to various beaches around Lake Michigan, including our neighborhood near Antrim Shores. She also writes about current issues pertaining to Lake Michigan: The Asian Carp situation, the recent oil spill on the Kalamazoo River (and what a mess that is!), and other related environmental concerns.
From my initial perusal of her blog, it's clear she's gotten a lot done! She's had tons of press coverage, knows her stuff, and in a recent email exchange, informed me that she walked along the beach in front of our cottage last June (of 09). Who knows, maybe we were sitting on the beach when she passed by!
I had initially hit on an entry about “tumbled slate” (see photo just below) and then found her entry on “Antrim Shale” and “Ellsworth Shale.” The tumbled slate she discovered on Fisherman’s Island State Park near Charlevoix, a five mile stretch of unspoiled beach, not 15 miles from our place, with boatloads of this stuff on the shoreline. Along with a photo of a handful of slate, she writes: “This was the only place along the lakeshore where I came across this unusual stone in this quantity.”
Her other two entries are from this year, when she revisited the beach near Barns Park in Eastport. Apparently there is an “Ellsworth Shale” deposit, not far from an “Antrim Shale” deposit. Ellsworth Shale, she explains, is green in color (top photo below), whereas Antrim Shale is dark gray or black (bottom photo below). I had NO idea! So, it would seem from her photographs that you can see the difference between slate and shale. I never knew there were shale deposits near Barns Park, and I never knew there were two types, or two colors, each named after nearby communities.
When in doubt about the difference between slate and shale, you can test it by scratching it with a knife. As Loreen explained in her email to me: “shale will score, slate will not.”
The sun burns hot on your back and shoulders as you step forward along the rocky shore, the cold waves washing over your bare feet. If you’re lucky, there are places of hard wet sand to walk, but mostly the shoreline is so rocky, the stones stab the soles of your feet. Still, you walk. The soles of your feet were leather-tough from summers of bare-footing when you were a kid, but now you’re a pussy, and stumbling along gingerly, you swear: “Shit, shit, shit!” You weigh a lot more than you did as a kid, too, and you decide next time to wear your old tennis shoes or a pair flip-flops.
You keep your head down to watch where you’re stepping and look for stones. They come in all shapes and sizes, all colors and textures, from tiny pebbles to massive boulders. As the waves tumble over them you can see the colors: round black or green basalt; red, pink, and black granite; brown, red, or white-gray chert; round and flat chalk-board slate; white or yellow, sometimes pink quartz; sometimes mixed basalt and quartz; a variety of fossils with a variety of patterns and textures; and a million other crazy layered or mottled mixes of all of these, all the colors of the rocky rainbow. They glisten along the shore, and they wobble and waver where it’s deeper, magnified by water and sunlight.
Lake Michigan and the other Great Lakes, according to Lake Michigan Rock Picker’s Guide, have more varieties and colors of rocks than anywhere else in the world. But along the shores of Grand Traverse Bay and the northern shorelines of Lake Michigan, you can also find Petoskey stones. They are fairly easy to spot along our shoreline, especially in the spring when new batches of them have been pushed up by last winter’s ice. They were named after Ottawa Indian Chief Pet-O-Sega, whose name means ""rising sun" o "rays of dawn,” or sometimes "sunbeams of promise.” Petoskey stones are generally gray in color, and when wet or polished (sometimes dry), show the classic mottled, fossil pattern of connected hexagonal shapes, each one with “rays” radiating from a little black “eye.”
Petoskey stones were formed from the coral, Hexagonaria Percarinata, whichcommonly populated the coral reefs in this part of the state during the Devonian period 350 million years ago, when the land of our state was situated on the equator beneath warm shallow seas. Each of the little eyes and rays we see on Petoskey stones were actually Individual “polyps,” each of which secreted a limey substance that hardened into a “corallite,” a skeletal base for support.These once living creatures multiplied in tight knit colonies, some colonies bigger than others, some polyps bigger than others. The surface of these colonies formed a dome of hexagonal food intake openings or “cups” that were surrounded by stinging tentacles used to catch and immobilize plankton.When the land moved north and the seas poured off, and each of their little lives was over, mud and silt made up of calcite, silica and other minerals filled the polyps and replaced the various elements in each one in a process called “petrifaction.” These fossilized corals were later picked up by glacial ice and dumped around the northern part of the Lower Peninsula.The fresh water and sand of Lake Michigan have been tumbling them around for the last ten-thousand years, rounding and smoothing them into the Petoskey stones we find on the beach today.
I remember the story from school days, of a giant Indian who pressed his hand on the side of the earth, leaving land in the shape of Michigan. Michi gami, in Algonquin means “large lake.” Other legends say Michigan is the hand print of Paul Bunyan. In another childrens' story book called “The Legends of Michigan” by Trinka Hakes Noble, the Great Gitchi Manitou and a young warrior boy raised their double-deer skin mittened hands to the North Wind, who left snow and ice to cover the land year round, to get him to north of Up North where he came from. The North Wind blew and blew with all his might but could not fight against the deer-skinned mittens. Fearful of losing everything to the Great Spirit, the North Wind tried to bargain. In reply the Great Spirit said “For three moons each year your cold winds can rule the land. “Only three months?” said the North Wind. “After the South Wind sends in Indian Summer,” the Great Spirit told the North Wind, “your cold winds may change the leaves of trees orange, red and golden yellow, but the pines must stay green.” The North Wind agreed and retreated back north of Up North. Thus, the four seasons returned. The ice melted and set the rivers flowing and filled the lakes, leaving the land of Michigan with deep great lakes of blue water. But, if the north wind should ever return, the Great Spirit left his double-deer skin mitten on the land, and this is how Michigan got its shape.
The legend closely resembles our geological history. In fact, the shape of Michigan, and our own Lake Michigan, is the result of varying degrees of resistance to erosion as the glaciers moved forward and back.
What really happened is this: in the beginning, the earth spewed up hot lava. It spewed it up and hardened, and spewed up some more on top of that, piling up in layers. Underneath it all, the earth sagged, leaving immense basins with hard, layered floors of basalt and rhyolite. Rivers flowed into these basins filling them with sand and mud made from sandstone and limestone. Then the climate changed—it snowed and didn’t melt in summer, and snowed and didn’t melt, snow piling up and packing down hard into gigantic ice caps. The ice-caps covered the entire northern part of continent. As it became colder the ice caps moved south, as it warmed, they retreated north. This happened four times: up, back, up, back.
The last glacier, the Wisconsin ice sheet, according to Bruce Mueller and Kevin Gauthier in their book "Lake Michigan's Rock Picker's Guide" (and a great guide for rock pickers on Lake Michigan!) is what created Lake Michigan (as well as all of the Great Lakes). It did not, the authors explain, act as a bulldozer, like I have read elsewhere on the formation of The Great Lakes, but as a convey belt driven by sunlight on the northern hemisphere, carrying rock, which rolled south for about 63,000 years. The rock, sand, gravel and boulders it carried were deposited to the south, east and west of the lake. As glacier melted, it deposited the stone it carried in the lake and all along Lake Michigan's shores.
So the lake bottoms and beaches of most of Lake Michigan are rocky. There’s granite, the stuff this country’s mountains are made of, and quartz, a common mineral that comes in mostly white and yellow. Along with these two, there's also basalt and rhyolite, and amazingly, all kinds of wonderful, colorful mixes of all of these. There's agate, thomsonite, chert, and chalcedony. There's a variety of fossils, too, including everyone's favorite, and the ones my sister and I collected and sold as children: Petoskey stones.
Around the summer solstice,when the days were long and the sun was hot, my mother liked to rake the beach.When I was little, she’d get the heavy garden rake from the lean-to utility shed behind our cottage, haul it down to the beach, and start pulling at layers of washed up rocks, making a grating, god-awful metal-against-rock scraping racket.If it was a particularly quiet, calm day, you could hear the noise from all directions, from way down the beach or way up at the cottage.She raked to clear the stones away, or to try to clear the stones away, so she could lay her towel down on the sand.
There was plenty of sand, and plenty of rocks, plenty of stuff to rake away: clam shells and driftwood, sea gull feathers and dead alewives, the bleached-white exoskeletons of crayfish. She enjoyed raking, like she enjoyed hanging clothes on the clothes-line. Even when the washer broke down she’d take the laundry to the Laundromat in Charlevoix and stick it in the washer, then haul it back to the cottage and hang it all neatly from the clothes lines that hung between the trees way out back behind the lane. It was good exercise, she said, both the hanging and the raking. It gave her time to think, or clear her head. But she found raking the beach especially soothing. Warm and sunny days of soft breezes off the bay offered an hour of peace, and that little bit of beach, the one that always needed raking, was her own little piece of heaven.
* * *
In 1953, lake-front property on the Great Lakes was cheap. Back then, lots on the east shore of northern Michigan were not necessarily desirable. The land was swampy and the soil acidic, abandoned by farmers soon after the land was logged off. The Great Lakes were often wild and rough, not much good for fishing peacefully off little boats. And the water was too cold and the bottom too rocky for swimming. If you wanted to farm you moved to the lower half of the state. If you wanted swimming and fishing and boating, you went to one of the quieter, gentler, small inland lakes.
My grandfather, Lyle Dickerson (we called him “Pop”) was born and raised in Bellaire, Michigan, the place my father spent his summers growing up. Pop told my parents about the lots for sale on Antrim Lane. My parents, both art teachers in the public school system in Flint, chose a lot near the dead-end of a rut road near a place once called Antrim City.
Thirteen miles south of Charlevoix, thirty miles north of Traverse City, it cost my parents five-hundred dollars for the hundred feet of beach front six-hundred feet deep with timber so thick (the second forest growth after the clear-cut lumbering around the time of Antrim City) it was near dark in the woods even during day-time hours. Away from shore the land was wet and muddy—swampland—infested with poison ivy, mosquitoes, and big black horse flies. Here were beech, maple, and birch trees, along with a variety of pines: hemlock, white pine, aspen, and fir. Along the dryer, well-drained shore grew an abundance of cedar, hemlock, and spruce, a beautiful green backdrop to the sun-lit beach and blue water bay.
Years before my sister and I were born, our father (our mother’s hero), with ax and saw slashed his way through the new forest growth, just as the settlers must have years before, scraping knees and elbows as he cut away at ground hemlock and branches from cedar trees, wondering as he worked if this was such a good idea (all ideas were Mom’s; Dad did the grunt work). He made his way to the edge of a twenty-or-so-foot bluff above the beach. It was one of Lake Michigan’s quieter days, he later told us, the bay dead calm, one of those days where chopping and sawing resounds for miles, echoing back through the woods and out across the bay.
When he finally broke through the tangled pine mess, he called to my mother, who followed his voice to the bluff above the shore. That’s when they saw Grand Traverse Bay, the Leelanau Peninsula directly across, and Lake Michigan to the north for the very first time. It was enormous, they said, a deep blue inland sea as big as an ocean. Along the shore they saw stretching, in both directions and beyond several points, a deserted and un-touched sugar-sand beach. The waves rolled in quietly, rippling northward along the shore. This was it, my parents at that moment decided; this part of the world, this one little spot, was theirs: a place they could call their own, their very own summers-at-the-lake.
On teacher salaries, my parents made yearly payments of one-hundred dollars. After a couple of years they nearly sold, struggling to come up with the cash. But they did make their payments and five years later, when the place was paid off, a company from East Jordan came out to clear the lot, cutting down some of the birch and pine trees, leaving a few tall hemlocks at the edge of the bluff and near the rut road in back. A cabin-building company from Bellaire erected a tiny cabin from a kit not long after my three older brothers were born: four log walls and a roof on a cement slab. The cost: eight-hundred dollars. Again, they had to make payments. My sister and I were born five and seven years later.
And though this was no calm, inland lake—sometimes the waves beat fiercely at the cliff’s edge and our boats and our toys washed away; often the wind bent the hemlocks nearly in half, the thunder during summer storms so loud our mother made us sit away from the plate glass picture window lest it should shatter, the rain pounding down so hard on the rooftop we feared it would crash in—we too, learned the value of summer-at-the-lake.
* * *
Over the years, the Great Lakes swelled and the shoreline moved up closer to the bluff. The beach began to lose its sugar sandiness, the bay throwing back rocks more often than it washed them out, layers of washed up stones digging into our bare feet. Over the years, our father watched us so our mom could rake the beach.
She wore her black, or blue, fifties- style and later sixties-style bathing suit and always wore a floppy beach hat. You could hear the grating sound of the rake against the rocks in the peaceful quiet of early afternoon, when the sun was the highest and hottest, from all the way up at the cottage. She was raking her own little square of paradise, keeping it tidy and free from clutter. After raking, she enjoyed an hour of beaching. Only the sound of gentle waves could be heard, the slight breeze rustling through the pines, maybe the sound of a Coppertone-lotioned hand flipping the page of a paperback. Maybe my dad listened to the Tigers on the radio on the porch swing. Now and then we’d hear that Coca Cola commercial—I’d like to teach the world to sing, in per-fect har-mon-y.
Our fascination with Lake Michigan’s beach stones started a long time ago. Several years before we were born, our parents bought our place on Grand Traverse Bay, near a little-known ghost town called Old Antrim City. In 1953, they paid five-hundred dollars for a hundred feet of beach front directly across from the Leelanau Peninsula. A few years later, they purchased their Bellaire-style cabin-- the cost for that: eight-hundred dollars. Here, we spent long summers, from early June to late August, from the time we were born until we graduated from college.
One of our favorite activities as children was collecting Petoskey stones along the shoreline of the bay, and for several summers we set up shop at Mel’s. From 1960 to 1978, Melvin Essenberg operated the Spider Sand Dune Rides on what’s now called The Antrim Creek Natural Area. On the corner of Rex Beach Rd and Old Dixie Highway (The Flat Rd) was Mel’s red and white “shanty,” his headquarters. Here, Mel allowed us set up our stand, where we placed our carefully selected stones in a pan full of water to more easily see the Petoskey stones' patterns-- the cost: a dime apiece. We had initially planned to charge a nickel, but our mother said folks would spend a dime as quickly as a nickel. We lugged our stones on foot (bare foot mind you; we rarely wore shoes in the summer), the mile and a half to Mel’s, often spending entire days under a shady tree near Mel’s shanty, though we often sat beside him in the shanty while he ate his packed lunch. By summer’s end, we’d earn enough money selling Petoskey stones at Mel’s to take home and spend at the county fair.
We still go to our cabin, whenever we can, and still have stories to tell: about our childhood and our place on Grand Traverse Bay; about Lake Michigan and it’s geology; the shoreline and it’s stones; and about the history of the area near Old Antrim City. And we still collect Petoskey stones, and other stones, too, primarily because it’s so much fun!
