It's not often that one can find a trove of fossils within one's vicinity-- in my case, within walking distance of my house. So time to spin a yarn and show some pictures.
There's a spot I've been returning to for going on six years now, and it has been pretty good to me in giving up its treasures. Nearly all of its material was trucked in, including rocks from the Bois Blanc, Amherstberg, and Dundee Formations. Of course, it stopped being productive by end of last year, and although it is provided me with fantastic pieces of trilobites such as Anchiopsis anchiops, Mannopgye halli, and Odontocephalus sp., among others, it's pretty much tapped out, with some areas being too overgrown now. Nothing left but splinters, mud, weeds, and dirt.
Still, I tried to give it a few more chances in the case of weathering or new material being trucked in. Nope. I've found nothing of interest there all year, so pretty much stopped going.
Nearby, however, is a different story. My new honey hole is also trucked in material -- too poor to make cement, so it is used as riprap / fill -- and there is a lot of it. Perhaps so much it may take me a very long while to tap it out.
Initially I thought it might be local Dundee Fm, and/or Lucas Fm (Anderdon Member) due to the sandy facies. Now, I think it may actually be Bois Blanc material.
So I've done about two half-days of recon and prospecting to get a handle on the site and material rather than do a systematic all-day dig. This stuff, pending rock type, can be dense, dirty, fragile, brutally hard, blank, or ridiculously fossiliferous. There are massive dome-like corals amidst smaller corals of all kinds, but in some layers bryozoans dominate.
And these are some of the medium sized ones! When I started poking around, I thought to myself that it was just a resigned end-of-visit tapping of a few boring rocks.
And then I started encountering some familiar matrix, but loaded with these rostroconch.
And then a few nautiloid/ammonoids started appearing, too. But the really exciting trip-maker that turned around my whole day, and has rekindled my interest in taking some walks outside my house is this:
Yes, a basically complete (I'll know for sure with prep) Pseudodechenella sp. Not sure of the species just as yet. Finding these, or their byrozoan/coral thicket-mate Crassiproetus, complete is far from common. After finding this proetid, I gawped at it for a good few minutes, shocked by my dumb luck! After, I started finding plenty of pygidia and other fragments. That brings me to the end of day one.
On to day two. I needed to recalibrate my expectations so as not to think full trilobites would be popping out of every rock. I was right: I did not find a full trilobite, but something no less sensational. But here's a tour of some of the other finds first.
A whole lot of sea bed goodness.
Long and branching.
This amounts to a hill of b...ryozoans.
More Crassiproetus pygidia. Not pictured yet is a fairly large one (about the size of a silver dollar for those who remember what those look like).
But enough delay. The find of the day, and perhaps the week, month, or year, would be this unattractive fragment:
Yes, it is a piece of a trilobite pygidium. It looks lichid in its morphology, with the little tubercular surface. It is always a good idea when trying to identify something to assume it belongs to a much more common taxon (it is not as far for expectation to fall!), but in this case I couldn't quite figure this out. I initially thought Acanthopyge but the shape was wrong. I had seen this before, but my brain had entirely negated even the remote possibility it could be... that. No, not among the rarest trilobites in Ontario, certainly not. My thanks to my friend and trilobite expert Scott for not only saying it was possible, but in fact certain: this is a fragment of a Terataspis grandis! They are effectively only known as fragments, so this is an extremely lucky find. It also means I have ever more reason to go back to this spot again, and again, hopefully for a few years to come.
So now comes the game plan for collecting examples of each of the trilobites that occur in this formation. Here is what Ludvigsen (1979) reports, followed by my current collecting status (I've updated the taxonomic names):
Lesperance and Bourque (1971, 1979) seem to list a few more in their "amphigenia zone" such as Coronura aspectans and various other synphoriidae. There is also some ambiguity as to whether Trypaulites calypso and T. erinus may appear, in addition to Odontocephalus selenurus (of which I have a single cephalic fragment). Lesperance and Bourque are, of course, drawing from material in the Gaspe limestone, so correlations with strata in Ontario can be a bit tricky.