Ranger and I, or the wife and I, have walked the shorelines of many lakes and ponds. We’ve also walked many a riverbed. Years ago, on one of those walks, I saw something protruding from the rock. Using another shard of rock I pounded at it until a tiny fossil popped out.
I was hooked.
The scientific designation is Invertebrate Paleontology if you care to get technical about it. I no longer care to. To put it simply, Southern Ontario is lousy with fossils of creatures before backbones evolved. SPOILER ALERT !! If you’re a creationist, you’re not gonna like this, so ummm, go away.
While refreshing myself on the subject (for this post) I ran up against an old nemesis, the evil twin of knowledge … technicality. “Two lithotectonic assemblages in southern Britt domain have different histories of plutonism, metamorphism, structural development, and mafic dyke emplacement.”… Yeah, OK whatever. I can’t believe I used to understand all that crap. Not to make light of the efforts and advances made by todays, and yesterday’s paleontologists, and geologists, certainly not. However, the everyday blog reader isn’t looking to prepare for a semester’s closing exam in invertebrate paleontology. You want the fun and mildly interesting view. So here it is :
The fossils you’ll find in Southern Ontario limestone are between 360 and 570 million years old, long before the celebrated dinosaurs. The limestone itself is a fossil as it’s composed of the microscopic bodies of lifeforms which lived in the shallow oceans covering the area at that time. An interesting, and somewhat sobering fact about those times, is that in the fossil record of Southern Ontario, two mass extinction events occurred. One of them was the 2nd largest in the history of Life on the planet. Near 60 % of the total diversity of life passed into extinction. Ya gotta wonder what brought that on, and hope it doesn’t happen again anytime soon.
In the time of Southern Ontario’s fossil record, an important advancement made was the appearance of the first backboned fish with jaws. As well, the first moss-like land plants evolved, though Life was still primarily in the shallow oceans. Sadly, my personal favourite critter, the Trilobite, passed into extinction during this time.
A quick web search for fossil collecting sites in Southern Ontario will yield familiar names. Names like Craigleith, Arkona, Manitoulin Island, Hamilton, Orillia, Guelph, Green’s Creek. Though most of the locations named in magazines or newspapers, are vague references to sites I rarely found. Admittedly, a couple were stupendous but most were just an exercise in frustration. Your best bet for fossil hunting is to get friendly with the week-end watchman in a limestone quarry, which I used to do many years ago. Though I rather doubt you’d have a hope in Hell these days what with worries about everything from terrorism to self destruction. Your best opportunity would be an exposed limestone riverbed. The Otonabee, the Grand, the Trent, the Ganaraska, or the Ausable, to name a very few I’ve seen &/or collected from.
Any exposed limestone riverbed could yield collectable fossils. The trick with fossil collection is to know what you’re looking for, or at least what you’re looking at. I was once walking along a dry riverbed with hammer in hand, in search of fossils. When I saw the telltale signs of one, I’d tap it a few times to get a listen of the surrounding stone, and if it sounded right, I’d pull out my chisels and extract it. Out of my peripheral, I saw some guy watching me intently from the west bank. While I was down, gently chipping away at a sample, a pair of feet stepped into view. They were followed by a voice demanding an explanation as to what I was doing. If you’ve read any of my other posts, you’ll notice I’m a bit of a sardonic and belligerent smart-ass. So, if you’re gonna demand an explanation from me about anything (which I would consider to be none of your GD business), you’d better have 1 or more of 3 things : A badge, a gun, or an army.
“I’m extracting fossils” I told him, in a Batman type voice and glaring up at him from under my eyebrows. You see, I got these really bushy eyebrows, and really intense eyes. When I look up through my eyebrows, I can make a pissed-off predator look that’ll scare the crap outa ya. I developed the look when I was a kid, and I even scared myself with it in the mirror a few times. ‘Course, I can’t see much when I do it, but it looks really threatening.
“What if I want to enjoy those fossils ?” he demanded to know (like so many Enquiring minds do).
I told him, “Well then, first you’d spend 3 years studying invertebrate paleontology on your own time. Then get a hammer and chisels for Christmas, and away you go enjoying fossils”. He started mouthing off again and I was getting annoyed so I quickly stood up to face him. Whew !!! Fortunately my shoulders were the size of his hips (‘course, now that I think of it, I also had a prospector’s hammer in my hand). He quickly stepped back, looking as worried as I probably looked, relieved. But he was still full of self-righteous indignation at my crime against … ?
“What gives you the right to remove fossils from a public riverbed? Do you have a license to do this ?” he continued demanding of me.
“OK, I’ll tell ya what, you point out which fossils you want to enjoy and I’ll leave them for you” I offered. He naturally looked down and saw what 99.9 % of North America’s human population would see. A pair of cheap running shoes, and a gray stone riverbed. “You want me to leave this one?” I asked pointing with my hammer. “Or maybe that one there” this time pointing with my chisel. “How’s about that one sticking out from under your left foot ?” I asked. He jerked his foot up like I’d just told him he was standing in a pile of iguana sh!t.
He had no idea what he was looking for, nor at. He wandered off mumbling some threat of taking it up with the police. Yeah, OK, be sure to tell ‘em about my flying saucer too. They’ll care as much about that, as they’ll care about some guy chiseling fossils out of a riverbed (ya jerk!)
So the point here is that you need to know what you’re looking at, and what you’re looking for. Memorizing the shapes of fossils sitting in a guy’s hand, isn’t gonna get you very far out in the field, but it is an essential start. Just keep the shape and color in your head while looking at the limestone riverbed. Of course, they’ll rarely be sitting on top of the surrounding substrate. You gotta look for traces of fossils, the edges, the tips, the hint of something under the stone. Sometimes it’ll be just a segment of snail shell, another time you might see the discolored edge of a clam shell. More often than not, it’ll just be an suspicious mound in the stone riverbed. When you tap your find with the chisel to release the medium around it, you’ll expose it to sunshine it hasn’t seen in hundreds of millions of years.
If searching roadway rock-cuts, don’t approach the rock face, as it’s dangerous, not only to your safety, but you will be distracting other users of the road. The best place to find fossils on a rock-cut is on the top of the cut. Cleave off layers from the cut side, to make chiselling easier. Yes, it is a little dangerous since you’re kinda leaning over the edge to chisel layers off. That’s why I recommend riverbeds.
Anywhere blasted limestone rubble is used to control erosion, provides another rich spot to search. The blasting loosens the fossils from the rest of the stone, or better still, exposes traces of fossils without the damaging effect of water erosion. That’s the reasoning I used when I went to the quarry years ago. I’d walk straight over to the most recently blasted face and search through the shattered rubble.
A rarely encountered fossil vehicle is called a fairy stone or a calcareous concretion. These are found eroded out of river banks and are deposited at the mouths of rivers, just off shore and around the shorelines. They are found in Quebec and other sites around the World. There’s only one site that I know of in Ontario, near Ottawa.
The best time to hunt for fossils is just after a rain. Wet, rinsed off limestone reveals fossils best. Failing that, take a water container and brush with you, and splash/scrub any promising locations. If you spot a heavily eroded sample half buried in the rock, go for it anyway. The buried half might display remarkable detail. Early morning or late afternoon sunshine casts long shadows across the limestone bed, which can be quite revealing. A piece of chalk is handy to circle anything you want to come back to. It’s incredible how fast a promising spot can vanish if you take your eyes off it, even for a few seconds. One step in any direction, and the light angle changes everything. That will often leave you frustrated and annoyed when you try to find that spot again in a sea of gray. While on the subject of color, the paler gray the limestone, the easier it’ll cleave and the easier it’ll release its fossils. Once it starts to get dark, the fossils become harder to extract in one piece.
The picture below displays what the wife and I call the “dink-dink bag”. When I first started hunting fossils, she would sit under the shade of a tree on the riverbank enjoying a good book. Off in the distance she could hear the “dink! dink! dink! dink! dink! of the hammer and chisels on rock. Occasionally, she’d hear squeals of delight when I’d found something particularly exciting. That only happened a few times before the treasure hunter in her surfaced, and she walks right along with me now. I wish I could say my choice of spouse was the result of cleverness or careful screening. However, I have to admit, it was just dumb luck on my part. I’m not entirely sure what she’d call it from her perspective though.
My father once described his favourite sport, sailing, as hours of boredom interspersed with moments of sheer terror. I describe fossil hunting as hours of anticipation interspersed with moments of shear excitement. When I give that final “tap” on the chisel and the rock makes that hollow, popcorn sound my heart leaps ever so slightly. When I tap the fragment with the chisel to loosen-up the substrate, and a perfectly detailed fossil drops into my hand, that’s the ultimate thrill to me. No they’re not valuable (with a few exceptions). The value is in the experience, and the sense of discovery. It’s the realization that what you’re holding in your hand was alive more years ago than a human brain can comprehend.
I got tricked into doing a presentation to “The Children’s Library” one Summer long ago. The “librarian” told me that it was basically a 2 hour baby-sitting service compliments of the town library. That certainly helped make my 2 weeks of planning and practising feel worthwhile. The room was full of kids (I like kids just slightly less than I love cats). Fortunately, they seemed fascinated by the manner in which I explained the sometimes rather complex history of the planet. I thought I’d done well to teach them an understanding of the geological time scale. While speaking of the comparatively recent geological phenomenon of ice ages, one little girl asked when the next one would be expected. I replied “Oh, right about now”. I meant, considering to a geologist “right about now” means plus or minus 30,000 years. The room went dead silent. A few started crying and the little girl who asked the original question asked “What are we gonna do?” and then she started crying.
OK, so I guess I didn’t get the concept of geological time scales across after all. I’d terrorized a room full of children into thinking they’d wake up in the morning as a 2 mile high wall of ice pushed their homes into Lake Ontario. Fortunately, there were a few experienced parents in the room who laughed it off as I explained that to a geologist “right about now” means plus or minus 30,000 years. That seemed to work, as the general consensus around the room was that 30,000 years was far away enough to be of minimal concern. “After all, the Sun’s only good for another 6 billion years” added one of those rare, remarkably well informed (and bloody annoying) kids who always show up at these things (you know, the Sheldon Coopers of tomorrow? Yeah).
Afterward, the parents, kids and myself went down to the riverbed (the library was on the banks of the river), and I showed them how to search for, and extract fossils. It turned out to be a pretty good day after all. Despite my revelation that the only thing worse than cats and kids, are their mothers (the kids’ mothers, not the cats’).