Although I said in my last blog post that the next post would feature the big spring dig, a lovely gift came in the mail today courtesy of Tony, a Fossil Forum friend. I had won a "guess the number" contest and chose an ammonite as my prize. Well, he added two Cambrian trilobites to the box, because that is just the generous guy he is.
The ammonite is from the Triassic of Nevada (possibly Frechites sp.). Let's have a closer look at the two ptychopariids...
The ventral view of a nice Bythicheilus typicum. This is described as a "fast-moving low-level epifaunal deposit feeder."
This is Bolaspidella reesae a lovely trilobite from the Wheeler Fm.
Ok, I promise the next post will be about the big dig. I just couldn't resist sharing this lovely gift.
With spring making its long delayed entrance, Deb and I made it out to Lambton County / Thedford area to do some collecting. This was mostly a run to fill up some buckets with fossil gifts for the US collecting comrades we'll be seeing this weekend, and also to get warmed up for that big trip, but we came away with a few nice things for ourselves, too. We even earned the classic "spring sunburn."
Within about 5-10 minutes at our site, I cracked open this full Greenops that is a medium size of 2.5 cm. It is complete, yet slightly buried in matrix. As I pulled this out from wet shale, I had to let it dry in the open for a bit before wrapping it up carefully so that it would survive the trip home. The cracks running through the rock may need to be stabilized before I take to preparing it.
The arrangement of these spirifers was worthy of bringing home, tesselated and lined up just so in a very busy brachiopod deposit. Some of them have the longer "wingtips" that often break off when these weather out.
Deb's find of the day was this complete Greenops, but as you can see it is on both faces of the rock. The left impression side has some of the shell sticking to it, and the rest of the anterior end of the bug hiding under the matrix. This will need to be carefully glued together, and then I'll have to prep down from the top.
We also managed to fill two buckets with gift fossils, and pocketed the usual other stuff including some larger partial trilobites and other odds and ends. This was a good outing in preparation for the weekend 3-site dig, which will be the focus of my next blog post. Until then!
The snow has (only briefly, I hope) returned once again and it is coming close to May. I'm hoping this will be the last blast of winter... but I think I've said that before! The weather looks like it will turn around for the weekend and return to normal seasonal values. And that is great news as I gear up for a four day dig at three sites in NY next weekend with plenty of Fossil Forum folks.
Speaking of Forum folks, one of our very generous members, Ralph, sent me a lovely package of trilobite partials he was able to pick up from a rock show. Ralph was also exceptionally kind in sending me (and several others) large boxes of Conasauga Fm matrix from Georgia, USA to play with, loaded with Cambrian trilobites.
Pictured here are three species of trilobite new to my expanding collection (standing at a whopping 76 distinct species now). Let's zoom in...
These are the pygidia of the Silurian phacopid, Trimerus delphinocephalus that occurs in the Rochester shale of NY. These trilobites are narrow and could grow quite large and somewhat resemble Dipleura dekayi in terms of shape.
A nice assortment of partials of the dalmanatid, Dalmanites limulurus, also from the Silurian Rochester shale. These ones do not preserve very well, and many of the ones for sale are missing the cuticle and their eyes, with some people choosing to restore them by adding eyes from other partials to make a frankenbug. That is fine if the seller is honest about the restoration (not all sellers are, though). One remark about the Rochester shale trilobites is that they tend to appear as though "listing" in the rock, leaning to the right or left.
Although missing some parts, this is another phacopid, Huntoniatonia sp. Without more diagnostic detail, drilling down to the species level may not be possible with this one. This one appears in the lower Devonian limestone of the Haragan Fm in Oklahoma, which is also famously known for producing some lovely spiny and horned trilobites like Kettneraspis and Dicranurus which usually only appear in Moroccan deposits. To some trilobite collectors, Oklahoma is like a little Morocco with the similarities between species, although with continental drift now thousands of kilometres apart from one another.
So, a lovely gift from Ralph once again keeps my spirits up while the weather is not cooperating fully with my digging plans.
Recently I was able to get up to one of our sites in Ontario with collectors Kevin and Matt after some aborted attempts due to weather. Malcolm is due to join us next week for a 2-day trip.
There is an incredible amount of work to do to get this site up to productive par. Winter saw the collapse of the upper erosion-resistant shelf, and as it tumbled it took a lot of overburden down with it, burying all of last year's benches.
This is what the site looked like in January when I paid a short visit during a temporary thaw. To give a sense of scale (since I failed to do that in my haste taking this shot), those blocks are about 3-4 feet high. Up behind were the benches we had been steadily making last season, now buried.
Last season was very good at our site once some of us were able to get down to one of the productive trilobite layers, and it was fairly common that a day's digging would mean going home with 2 or more full specimens. It was the result of many hands working those benches, expanding them, and getting at a layer that pulses here and there, pinching in and out.
We arrived in the morning with our arsenal of tools, prepared to do a lot of site preparation work - shovels, picks, the entire spectrum of hammers.
A picture of Kevin.
At this point, Kevin and Matt had been able to open the bench back up a bit more after Malcolm had done some work the previous week. The problem is that we have lost our layer, and it is still uncertain if what is below our feet here is already exhausted (likely is), and so there is little choice but to bite deep into the cliff and work our way down. This is not as easy as it sounds: for every foot deep we need to expose, there are about 6 or more feet of overburden and shale blocks to remove - and this increases the deeper you need to bite into the slope.
The other challenge is that a lot of these blocks are interlocking at various angles, and they need to be "unlocked" by removing key pieces as you follow a fault, some of which go on for a long time. It is not uncommon to think the fault will end only to find it wander in far and intersect with another fault that needs to be worked first, and maybe another one that jumps ahead in the sequence. What may look like a simple unlock of a slab and removal becomes complicated and even more labour intensive in a hurry.
Matt and Kevin up at our bench.
We put in a solid six hours of work to expand this, and we are not anywhere close to exposing enough to get this site productive again. As you can see above, there are three "hollows" that each of us worked. I worked the middle one where Kevin is sitting, spending all day on just one stubborn slab that was interlocked in four places and would simply not let go as there was no point at which it could be dug in and levered out.
Some weathering will need to take place. We constantly bumped up against layers that where the matrix was dense and would simply shatter into shards rather than come out large and clean, leaving a messed up jagged face. If our tools cannot find a place to bite deep and gain purchase, the shale just chips off diagonally across the splitting plane. That set up for an agonizing game of inches, always in the hopes that we could find that right piece to unlock the shale puzzle.
Fossils from these upper layers were of poorer quality, mostly. Very turbid, agitated deposition environments that gave up a lot of bits, or were otherwise just stuffed with brachiopods (which become a bit of a nuisance quickly). A few very thin nautiloids were spotted, but none of those nicely plump pyritized and ribbed ones. There were zero ammonoids apart from some traces of living chambers, which told me we were not quite yet at the layer we needed to be as those are heralds of coming close to the trilobite layer. Pyritized worm burrows, brachs, and trilo-bits dominated the rocks. We're still too high up in the strata, so we are still trying to dig in, and then down.
We'll know when we hit that trilobite layer as they tend to congregate together. The general rule is if you find one complete, take it home and probe the matrix for more.
As for the site itself, it is still going to take a few more long days to get it ready for the season. The tricky part is in planning the day so that we don't do all the excavation work in exposing the layer, have to leave at the end of the day, and someone else simply exhausting it without having done the grunt work required. But this site is nowhere near the point where that is in danger of happening. We also reason that we are coming close to this particular exposure having one last good season in it before it becomes untenable to work it anymore as we are losing the slope, and would probably have to work down 20+ feet of rock from the top to create new benches.
Each of us came away with 3 or so potential full ones, mostly damaged. These are the isolated full ones you can expect to encounter in the bits and pieces layers, and their preservation is generally quite poor (and they are flaky and delicate to begin with). Here is one of mine missing the the left part of the cephalon and the anterior portion of the glabella. A prep practice piece, or fodder for reconstruction parts.
In all, the trip was all about site preparation, not so much fossil finding. That will come, but only after we put in quite a few more days of heavy digging, hammering, and hauling. It was fantastic to work alongside Kevin and Matt, as they are a great and hilarious bunch of guys. When we trudged back to the cars at the end of the day, Kevin set me up with an Isotelus "mafritzae" that he expertly prepared. Kevin prepares and sells trilobites almost exclusively to high end clients, and this trilobite here - as top shelf as it is - is hardly representative of the gorgeous pieces he finds and prepares.
This may bring my winter asaphid purchases to their conclusion for the season as it is time to collect from more than just the postal formation! And I may as well end it with a proverbial bang.
This whopper of a bug is Asaphus raniceps, clocking in at about 100mm. You can make out some minor restoration, which is fairly standard.
This googly-eyed monster is the intermediate species between Asaphus punctatus and A. kowalewskii: Asaphus intermedius. Okay, not the most creative and inspired example of binomial nomenclature, but it underlines the point that this is indeed an intermediate species. These sky-high peduncles were a response to increasing turbidity in the Iapetus Ocean. Their entire bodies would be buried in the sediment with only the eyes showing - ideal for hiding and predation.
This is a rubbish shot and arrangement, but I'll be organizing this properly later. I just wanted to show off the collection of these Russian googly-eyed asaphids. Absolutely beautiful, and I am quite proud of how I managed to collect so many... Although they were not cheap!
Today I received a few packages in the mail, including one Czech trilobite and five Russian ones.
Here, four asaphids and a corynexochid are gathered around a trio of ptychoparids. A reflective moment for these Ordovician trilobites with the much older Cambrian trio in the centre.
This is Ellipsocephalus hoffi from Jince in the Czech Republic, Cambrian in age. This is a nice assemblage. These are what are known as blind trilobites as, well, they have no eyes!
Illaenus sp. (?oblongata), a Russian corynexochid from the Ordovician.
Readers of this blog might recall when I was preparing an Asaphus lepidurus not long ago. This is what a full, professionally prepped one looks like.
Here is the same specimen on its ventral side, showing off a very nice hypostome!
This is definitely "wide-load" - Asaphus latus. Almost as wide as it is long.
The aptly named Delphasaphus delphinus fully prone and looking a bit like a dolphin... if a dolphin were a segmented arthropod from over 400 million years ago.
This is the biggest of today's acquisitions at over 76 mm: Asaphus holmi. Below is the ventral side showing its hypostome: