And this is where this fantastic, whirlwind, whistle-stop tour comes to an end: at the St Marys Cement quarry in Bowmanville. This quarry is massive, and it only opens up to collectors once or twice a year - and in that case, only to collectors who are part of a recognized club (and so Deb and I are new members of the Scarborough gem and mineral club). Safety is paramount at any quarry, and this one is no exception. Full safety gear is just the minimum, for there are plenty of other safety policies we are obliged to follow. We all assiduously follow all the rules as we want to maintain goodwill with the quarry owner. Violating safety is not only dumb and dangerous, but it risks collectors being entirely shut out from there forever.
And so we began gathering in the parking lot around 8 am. The quarry is known for producing a lot of Isotelus and Pseudogygites trilobites. The workers see some of these big creatures going up the conveyor to be crushed to make cement and call them "turtles." And these trilobites can get pretty massive.
This is how my day started. We had planned on just driving up to a hotel in Bowmanville, but they were all booked up. The one time I didn't book in advance since I figured, heck, it's Bowmanville... How hard could it be to find a place for the night? Famous last words! Fortunately, the kind staff at the local hotel called around and we got a place just 14 km up the road in Oshawa. The picture above is a brand new day as we are leaving the hotel to join our collecting comrades at the quarry.
This is our crew eagerly awaiting entry. Our trip leader, Kevin, said that this must have been the biggest turnout for a day at Bowmanville. Weather may also have something to do with it: usually without fail the trip occurs when it is cold, rainy, or both. On this day, it was warm and sunny.
This is a serious quarry. That truck on the right has tires taller than me!
Once we signed our forms and had the safety talk from the quarry foreman, we formed a convoy of cars and entered the quarry. This quarry is so large that you actually do have to drive from one blast pile to the next. Many of us started at level 3. Those piles aren't tiny, and you are scrambling up piles of rock that can in some cases be the size of small apartment buildings.
Yours truly giving closer inspection at a low-lying pile. Scale is tough to make out in this picture, but that wall in the background is probably about 300 or so metres away. The "trick" at this quarry is not to stay in one place to split rock, but to cover a lot of ground. About three of our crew have rock saws, and so what you do when you find a great specimen in some car-sized slab of rock is to mark it with tape so that at the end of the day the guys with saws can cut it out for you.
My first find of the day: a beat up Flexicalymene. The stratigraphy of the quarry has a lot to offer. At the very bottom is the Verulam Formation (the dominant unit at Brechin), and over top that in levels 2-3 is the Lindsay Formation. At the very top is the Collingwood Member with rich black shales that are easy to split.
The Isotelus trilobites here are huge. Sadly, you mostly encounter fragments. This piece here would have belonged to a critter at least 14 or more inches long.
Massive genal spine, likely from an Isotelus mafritzae.
Someone got to this one before I did! That lucky collector hopefully got this one cut out of the rock. It looks like an intact Isotelus roller. Apart from some blast/quarry damage, it is likely complete.
Another early part of the day find, a partial Isotelus mafritzae. It is sadly a common feature that the eyes get busted off. I don't want to give the impression that the collecting was as simple as stumbling over thousands of this lovely fossils: you could scan quite literally hundreds of tons of rock and find very little beyond occasional fragments. Apart from some occasional brachiopods or crinoid stems, there isn't a lot of diversity in these rocks, so it is pretty much trilobite or bust! It's also rough going... I was having to scramble over enormous building-sized piles of rock with a bucket and heavy backpack on uneven slabs, so not so easy as it looks!
Some of our more seasoned veteran collectors didn't make out so well this time around. One found a few mostly complete Ceraurus, and another collector find a nice plate of full - but somewhat damaged - Pseudogygites, but some of our best collectors made out poorly or were entirely skunked. But at the very least, I think everyone came away with something even if it wasn't a prize and pristine Isotelus. More importantly, it was great to hunt with everyone.
This is just part of the head of an Isotelus. It would have been, full, at least 13 inches long! This was an encouraging find as I was gradually becoming a bit more discouraged in not finding anything complete.
Another sweet, if incomplete, find. The trilobite Pseudogygites latimarginatus also occurs in this tough limestone, but unlike how it appears in the upper member of the Collingwood shale, they come out with a fine exoskeleton texture and fully inflated rather than flattened. This one I carefully extracted from a very large slab. It has some thorax, which is much better than the zillions of just tail moult pieces one usually encounters. Pseudogygites and Isotelus are effectively closely related species.
partial roller missing a lot of parts.
I put the biggest fragments I came across into the collecting bucket as a souvenir of the trip.
Just... wow. A fragment alone almost a foot long!
I pulled this rock out that had a thin line running through it which I suspected to be an Isotelus. When I got home I split it and out came a fragment. A fairly mighty one.
As our time was coming to a close, Deb and I made our way to the uppermost level where there are enormous books of black shale belonging to the Collingwood Member. There are quite literally thousands of Pseudogygites latimarginatus and Triarthrus eatoni moulted bits among the brachiopods. Finding a full one of either is not easy, and so you have to split shale in massive volume. Fortunately, it splits easily and finely, and it is like the pages of a book. If I had a trip-maker, it might be this small but full Pseudogygites above, showing both the positive and negative impression.
So, wow. What a trip it has been! Three days spanning over 400 km and three quarries - Arkona, Brechin, and Bowmanville. I was able to collect with old friends, and make new ones. Although I don't think I found anything scientifically significant, I did manage to collect some very nice specimens (including that pair of Greenops on a single plate!). I was able to add two more species of trilobite I did not have (Amphilichas ottawensis and Isotelus mafritzae).
I'm hoping this will be an annual tradition from this point on. It sure is exhausting, though! But the thrill of the hunt, the camaraderie of being with other collectors, the sharing of knowledge, and all that lovely fresh air and sun does one good.
Reflecting on October, it has been a great month for collecting. I've been to Arkona a few times, to Brechin and Bowmanville, three days at Penn Dixie, and even found a new species of trilobite in my backyard region. And inasmuch as October has been a true surprise, this year has long ago distinguished itself as the absolute very best year for all things fossil. So what's next? Winter is just around the corner, and maybe - just maybe - I might be able to squeeze out one or two more trips before I have to put away the hammers for the season. But with my air eraser, and my air scribe coming, I can at least spend those cold, snowy months preparing all that I have found this year.