It was just a week ago that we spent all day carving out big slabs of Widder shale from the productive Tornoceras layer above the brachiopod layer. With the weather holding on to summer by its eye teeth, it was an impromptu invitation from a fellow TFF member, Kevin, who is part of a fossil club that saw us loading up our tools and spending our Saturday in the sun.
We began in the south pit. I spent the morning digging into the high energy coral biostrome of the Hungry Hollow Member, picking through the softer, shale layers. Apart from large rugose corals, there are brachiopods, pelecypods, bryozoan colonies, and trilobites. Because the deposition conditions were turbid, high energy environments, most trilobites only appear as fragments.
Pictured here is one of many of the large trilobite fragments that can be found in this layer. The most common species in this layer is Eldredgeops rana. This one is fairly large, even for this site as evidenced by this plump and inflated glabella. Prepping it a bit more, this one is nearly 2 inches wide.
When I first found this one in the biostrome, all that was showing was the glabella. After some prep with a Dremel and then sewing needle, I uncovered more of the cephalon, but also discovered another cephalon to the bottom left. Sadly, neither are complete, but I was happy to bring out some detail.
The second most abundant species in this layer is Crassiproetus candadensis. Pictured above is how one usually finds them: mostly pygidiums. The crushed one on the right has a slim chance of continuing into the rock, but I am skeptical.
By the afternoon, we made our way to the north side, and I took others to my favourite cliff exposure. This spirifer is quite nice as they can be very delicate, so it is not common to acquire a matrix-free one with its wings intact. This one is over 2 inches wide.
I spent almost four hours in the same spot extending a bench and moving about 30-40 cubic feet of shale. I mostly had to remove a lot of overburden and layers of less productive shale to get to my coveted low energy layer that rests atop the hard brachiopod layer, but also has a chance of finding very nicely preserved ammonoids and nautiloids. The productive layer is about 3-6 inches thick. Again, I failed to find a fully complete and pristine Greenops widderenesis, although the fact that they appear mostly complete as opposed to lots of shredded bits increases the probability of encountering one. I collected this for practice prep as I am expecting a Paasche air eraser in the mail in the next week or so.
Of the 4 or 5 I collected on this day, this one was in the middle of a large slab of shale. It took a lot of careful finesse to extract it without having the shale split through it, or the vibration of the extraction process knock off any of its delicate and flaky shell. This one will clean up fairly nicely.
I don't usually bother with fragments unless they have something special about them. In this case, the cephalon is much larger than one typically finds for a Greenops. This one is over an inch wide. Typically, the species is a little over an inch long. On the right is an impression with some of the shell sticking to it.
Last week I found a large and inflated Tornoceras uniangulare. So why not find another one? This one is slightly smaller and thinner than the one I previously found, but the detail on this one is fantastic. I think it is a gorgeous specimen.
Not pictured would be my usual assortment of odds and sods I always found at Arkona. Although once again I was skunked on finding a pristine Greenops, I still made out very well, and got to collect with two members of the Fossil Forum, too.
Lastly, this piece was not found in Arkona, but I rediscovered it while going through a trip bucket. I picked this up from the Verulam Fm in Brechin. Is it a big crinoid head? Nope. It is an ichnofossil; i.e., a trace left by an organism or organisms. In this case, it is Phycodes ottawense. This mop-headed piece is caused by worms burrowing repeatedly into the sediment from the same spot. Worm burrows bore me to bits, but this one was worth picking up due to its neat appearance.
But stay tuned: there will be at least three major events coming up: 1. Cleaning up a lot of fossils with the new air eraser once that comes and I get a good air compressor; 2. A multi-day trip return to Penn Dixie in October; 3. A possible trip back to the Ordovician on the hunt for Isotelus in Bowmanville in late October. Even without those upcoming events, this has already been the best collecting year ever.