Imagine a warm and shallow sea, one with billions of small creatures skittering about across the silty bottom.
These flat, hard-shell creatures, kings of the sea as they were and the top rung of the food chain, dominated their underwater world.
Fast forward 455 million years and you will find a few of these wonderfully fascinating little guys sitting on my desk, frozen in time to when they were buried by fine sediment, perishing from their world, waiting to be rediscovered by some guy with a hammer and chisel sitting on the shore of southern Georgian Bay on a sunny Sunday getting sunburned because he forgot his wide brimmed hat.
That guy would be me and the shoreline is at Craigleith, just a stone’s throw west of Collingwood, on Georgian Bay.
Sitting on the rocky shore with a four-inch-thick slab of black rock the size of a dinner plate, I whacked the chisel with my hammer, splitting the sedimentary rock along its edge into two equal halves.
There is an immediate smell reminiscent of old used motor oil when the rocks break apart.
These rocks, called oil shale, are extremely fine-grained, black and are organic-rich sedimentary rock from which liquid hydrocarbons can be produced, along with strong-smelling bitumens.
Inside, revealed to the blazing sun for the first time in hundreds of millions of years, are small trilobite body parts which blanketed the bottom of the sea at the time they were buried and preserved for eons.
The extremely fine sediments of the area helped preserve even the most intricate features of the ancient animals.
Almost all of the body parts are cast offs of a specific trilobite, named Pseudogygites latimarginatus, after they moulted their shells when they grew new ones.
Once in a while, if you are lucky, you can find entirely complete trilobites in all their glory.
That’s the prize for fossil hunters like me.
Trilobites are ancient arthropods distantly related to crabs, lobsters, spiders and insects.
They have a hard exoskeleton and jointed segments such as a thorax, which are classic arthropod features.
The sedimentary rock they are preserved in is almost as fascinating as the “bugs” themselves, as serious collectors call them.
When you arrive at Craigleith Provincial Park, established in 1967, and created to help preserve the historic oil shale beach, you will find a roadside historical plaque which describes the history of the mining of the oil shale rock.
It reads as follows:
A growing demand for artificial light led to the establishment, in 1859, of a firm headed by William Darley Pollard of Collingwood. He erected a plant here to obtain oil through the treatment of local bituminous shales.
The process, patented by Pollard, involved the destructive distillation of fragmented shale in cast-iron retorts heated by means of wood. The 30 to 35 tons of shale distilled daily yielded 250 gallons of crude oil, which was refined into illuminating and heavy lubricating oils.
The enterprise, the only one of its kind in the province's history, failed by 1863. The inefficiency of its process made its products uncompetitive after the discoveries of ‘free’ oil at Petrolia and Oil Springs, near Sarnia.
Other fossilized critters which can be found residing among the trilobites in the oil shales are brachiopods, graptolites, cephalopods, pelecypods, gastropods, and conularids.
Google them for descriptions and examples, especially graptolites and conularids, which are rarer and fascinating to science nerds like me.
Once or twice this summer, you will likely find me perched on a boulder busting open rocks on the shore, which for some weird reason, I have no problem doing for countless hours on end.
The provincial park is a great place to look at exposed and weathered specimens, but be aware, visitors are not allowed to take any from the beach inside the park.
Public beaches in the areas outside of the park?
Have at ‘er. Fill your boots. Go to town. Whatever colloquial phrase you prefer.
And bring along a friend — get them hooked on the hobby when they discover a beautiful specimen all on their own.
I thought my wife would get bored with it pretty quick, tagging along with me on my excursions, but she loves it.
One of my pals, Mike Meacher, who appreciates trilobites more than anyone I’ve ever known, almost to the point of being unhealthy, has made collecting and preparing of trilos his career, under the moniker of Stormbed Paleontological. The gallery on his site is extraordinary.
His collected specimens of various species from all over North America are jaw-dropping after he gets through with them. They are so lifelike, and they appear they are about to walk away from the rocks they sit on.
Mike tells me he can often prepare high quality trilobite specimens he collects from Ontario or New York in an hour or so. Ones with a harder matrix and/or fragile pieces can often take him dozens of hours.
He says splitting the rock is the best way to find complete trilobites. Oftentimes, this will result in parts of the trilobite being stuck between the positive and negative slabs of the rock.
These cases are much more time intensive as the pieces need to be glued together and he will have to mechanically work back down to where the trilobite is located in the rock.
Mike’s preparation technique consists of a combination of micro air abrasion tools, scribes and rotary tools for finishing work. All of this is done under a stereo zoom microscope.
The Craigleith area and Georgian Bay hold special significance to Mike, as he was born in Collingwood and his father grew up literally on the oil shales of Craigleith.
“When my dad was a kid, field workers from the ROM (Royal Ontario Museum) would come to the house to see what new fossils he had found,” he tells me.
Growing up, Mike heard so many stories about trilobites and the fossil packed shale that littered the beaches, and was obsessed with the stories about trilobites from an early age.
“Sadly, this once great collecting site is covered with housing developments, and the residents are hostile to collectors. The Craigleith area will always be part of me and if things ever change, I’ll collect there again at the first opportunity.”
Kevin Lamb is a reporter at BarrieToday.
