After about 15 or so hours, this bug is coming along... but not without hiccups along the way. The first challenge was that the bug dips into the matrix on an angle, and this is not exactly butter matrix; my ARO clone was having a hard time planing down with a lot of stalls. Blasting it with the Paasche at 60-90 PSI was not an option either as it was not working to get off more than maybe less than a micron at a time!
Although a robust bug, bits would come off that needed to be retrieved and glued down. The second eye also popped off and needed gluing.
Still more work to do, but the scribing is pretty much done. Judging by the presence of a genal spine on the right, this is Isotelus "mafritzae" morph type "A" (not "B" like I initially thought). The cephalon looks like it should continue on the right, but it is folded in and crushed.
I'll be updating this post in the coming weeks.
1. The right eye has some serious issues that I need to tidy up.
2. Cyanoacrylate that was used to stabilize the right side pleura still needs to be removed.
3. Several areas that need restoration; I'm just waiting for my Milliput to come in the mail.
Below, I've greyscaled the image to indicate where some of that future work is required.
Amidst teaching and grading, I am spending some time at the prep bench. Deb got me an early xmas present: a much-needed shop vac as the fine dolomite dust covering everything in the basement is a sign that it is also coating our lungs! I'll be hooking up that bad boy this week.
After the recent Bowmanville trip (post here), prep has begun on a few pieces while leaving much of it for winter. I've also been voraciously reading several trilobite papers as of late during my long bus commute. But this post is more of an odds and ends one.
Kicking it off would be ongoing work on my Isotelus (likely I. "mafritzae" morph type "B"):
The going is slow when the rock is dense, and the bug is flaky. During a quick exploratory abrasion, I had that heart-stopping moment of a piece flying off and miraculously located it in the dusty, bit-strewn blast box (that I can now clean out with the new shop vac!). It was some cuticle from the occipital ring that I glued back on. The eye is intact, and I suspect the other one will be as well. This one is tucked into the plane on an angle, so that means a lot of long scribe work to bring it down. Nothing can be easy! In this case, it will be worth it, as it is only missing a few tiny pieces from natural weathering, and already seems to measure 90 mm.
A few weeks ago, my fossil comrade from Texas, Kris, sent me hot peppers he grew and dried. We are both hot-heads and love our super hot peppers. This nice selection includes the famous Trinidad moruga scorpion that taps out at over 1.2 million Scoville Heat Units (that is about 3-10 times hotter than a habanero). I am keeping a few in the freezer to seed and plant next year, and the rest were turned into hot sauce. The process is fairly simple: sterilize the jar in boiling water, reconstitute the dried peppers in boiling hot water for 15 minutes or so, cut off the stems, add vinegar and salt, puree in a small blender. But this is a fossil blog, not "Kane's Kitchen"!
Kris perked the package with some fossils! Here are some ammonites and a reptile vertebrae from the upper Cretaceous.
Some really neat fish and shark verts, as well as a shark coprolite -- also all from the upper Cretaceous.
A very cool pyrite piece showing the cubic crystallization state, and exceptionally well preserved and detailed leaves from the Eocene.
Those leaves truly deserve their own photo. In the interim, I've been putting a very Canadian package together to send his way.
I really hope to get out to collect one more time this year, likely to Arkona. That will depend on weather, opportunity, and the healing progress of an ankle I sprained pretty badly. If not, then I suspect the next few posts will be detailing preparation progress and a round-up on a year that has been hit and miss.
Had a pretty good time at the biannual collecting event in Bowmanville (east of Toronto). Although the first half was a complete and frustrating bust, the second half was when our luck turned. I've some prep work to do, but some field fresh finds should do for now.
Here's our crew. It seems that ever more people are coming out to this event. The quarry is so vast (six levels), that even with this many collectors poring over the blast piles there is plenty of space and opportunity to make some lovely finds. It's also nice to talk shop with other fossil-hounds. The main attraction are trilobites, and particularly large Isotelus.
Finding a complete Isotelus pretty much necessitates scanning and splitting through a lot of rock that are filled with moulted partials, some of which can be quite large. Pictured above is a few of the larger partials I took home, and one can imagine how big they might have been complete. And this is nowhere near as big as these can get.
Midway through the day, our luck started to turn. Pictured here is a Leviceraurus mammiloides of some significant size. Although the left genal spine is missing, the right eye is in the impression side, and I can prep out the pygidium to expose the long spines.
A not so great Ceraurus. As an added thrill, they can also be quite flaky. I can use this one for prep practice. The cephalon and thorax should be relatively complete.
Poorly lit photo, but I'll retake it once I give this one a quick blast with the air eraser. A fully intact, perfectly round and enrolled Flexicalymene croneisi -- a new species in my collection. You just have to love the duck-faced look of these.
Possibly a Thaleops on the left, and a Flexi on the right. Both obviously require some prep.
What I really came for: Isotelus! This being my third trip to Bowmanville, I had never found a complete one. This one has its head tucked into the matrix, so there is a chance the eyes are intact. In most cases (when the bug is exposed), the eyes are sheared off from blast damage or weathering. On the right was a small consolation specimen I picked up in case I didn't find a full one.
But wait, there's more! Well, not so much more in terms of trilobites (I have a few others I haven't added here yet). This big nautiloid chunk was worth taking home.
It's always good to break rock with good folks. It is always a great pleasure to meet up with Kevin B. with whom I've had collecting adventures. A professional preparator by trade and trilobitologist, I had entrusted him with a very delicate and challenging preparation job of three notoriously thin-skinned, enrolled Greenops widderensis from Arkona. The genal spines and lappets were flying. In the process of prep, Kevin found a fourth one on the plate. This is incredible and painstaking work. Here are a few other closeup images:
So, in all, a great time in the Lindsay Formation. And now the prep season begins...
While I had the compressor running, I figured I'd do a quick blast on what will probably be a very challenging prep this winter, as well as preparing some "low-hanging fruit" in the form of a prone.
First, the investigative quick air abrasion blast on this Greenops widderensis roller with flying genal spines. This one will certainly be a major challenge to do without screwing up. I'll probably end up cutting the rock a bit above the spines and delicately work my way down to reveal the other side.
This was the low-hanging fruit: a small Eldredgeops rana prone from my Penn Dixie weekend. The matrix is very thin on one side, so there was the risk of the trilobite flaking.
For this post, I will be showing the progress on preparing the largest Eldredgeops rana that I have ever found at Penn Dixie. This post will be updated once the preparation process is complete.
Taxonomy: Eldredgeops rana (Green 1832)
Geology: Mid-Devonian (Givetian). Hamilton Gp., Moscow Fm., Windom Mbr.
Provenance: Field collection (K. Faucher), October 13, 2018. Hamburg, NY, USA
Specimen is a large individual for the species and location, likely latter holaspid stage as opposed to simply being of an anomalous size at an earlier phase of development. Evidence of pronounced and widespread pustular sculpture may attest to this. Specimen is oriented in a semi-prone attitude with high convexity to mid-posterior thorax, with posterior thoracic area pointing downward. Specimen is also oriented transversely with a shift or dip leftward into the matrix. Compaction damage to the glabella evident, in addition to apparent crack in palpebral lobe (left side). Specimen measures (from anterior tip of glabella to final posterior thoracic segment) 60 mm along the dorso-saggital axis, and 42 mm on the transverse axis.
Windom Member shales present the conditions of rapid mud burial. Such catastrophic events result in more ideal conditions for preservation of well-articulated specimens, both body and moult fragments. Enrolment is a common feature as a defensive behavioural response to the sudden stimuli of these mudslides. Field observations (anecdotal) put the ratio of full prone, semi-prone, and enrolled specimens of E. rana in these layers as roughly 1::5::10.
Frequent ecdysis of the species furnishes several moults of isolated cephala, pygidia, and intact thoracic exuviae. These are commonly aggregated due to currents, or moulting grounds in gregarious groupings. Fused cephala (no cephalic sutures) meant that this species would commonly exuviate at the weakest point in the exoskeleton, between the cephalon and the thorax.
Taphofacies of this section of the Windom Member ("Smoke's Creek Layer") indicate a relative degree of bioturbation of muddy sediments, the presence of worms, and significant pyritization. Groupings of trilobite remains are generally sorted according to similar size, but this is not always the case.
It is so far assumed that the specimen appears as it did in its life position. No presence of predation marks, parasitism, or disarticulation due to hydrodynamics or decay. Being of a significant size, it also presents some distortion on its left side likely due to compaction.
Preparation of the specimen was undertaken using an ARO-based air scribe to remove bulk matrix, while a Paasche air abrader set at various pressures and using dolomite as the blast medium was used for detail work.
Specimen as found in the field.
After 1.5 hours
After 2.5 hours
After 4 hours.
Another few hours will be required to complete the preparation, including matrix sculpting and scribe mark removal. A smaller enrolled specimen was discovered during the preparation process, which will also require preparation.
2.5 hours later.
And pretty much as far as I want to take this one. Not perfect, but pretty close as I continue learning the art of preparation.
posting this on the final day of a three day dig at Penn Dixie in Hamburg, NY. Earlier in the week I dug with Fossil Forum friends in the Thedford area, and have been amassing finds over several trips. No pics of those hunts yet, but that will happen once the season is over.
We moved a lot of rock this weekend, and found a lot of trilobites. Pics of those when I get the chance. For now, site pics to show our work.
This shows the state of the dig area cleared out after Friday when I joined the other crazy Canadians. As soon as I got there, the human backhoe that I am went right into ripping out large slabs. The fresh stuff is where the best preserved fossils can be found, as opposed to the stuff that has been left to weather out. We do serious earth moving! The trilobites appear mostly at the Smoke’s Creek layer of the Windom Member, or the bottom 15 cm from the contact with the Bayview, just below the water table.
By the end of Saturday, it was mostly just me and Deb, with Jay popping by. Thanks to him for supplying me with wedges. I carved out the slabs while Deb broke them down. Pictured above is the view from one end of the excavation. I managed to double the area (to the shovel handle in the background). The photo hardly does the size of this much justice.
There are a lot of fossils to photograph (about two 5 gallon buckets so far), giving me a lot of winter prep material. This one above is among the largest Eldredgeops rana trilobites that can be found here. This is going to prep out beautifully. A semi-prone position with pygidium tucked underneath. Rollers are common, but prones are not as frequent. I also found a Bellacartwrightia (looks like a Greenops on steroids) in ventral position. Lots of rollers and prones were found.
Some snaps of me caught by our shutterbugs on the Friday. Top two photos by Monica P., and bottom two by Ken M.
And this is how we left the place on the Sunday. Some serious excavation as about 250 cubic metres of rock were extracted and split.
Several buckets of goodies were collected, and these are a few of the better pieces. These are being kept as-is until winter prep time.
Full prone Eldredgeops rana in an assemblage with partials/moults of similar sized specimens.
Ventral side Bellacartwrightia sp. with doublure and intact left genal spine in evidence. Although a ventral prep is possible, I may stabilize this and prep it dorsally. It is uncertain if this is complete beneath the matrix, or just the cephalon.
Pygidium showing of a Greenops sp. Unclear yet if it continues into the rock, but the presence of thoracic pleurae is a positive sign. Sadly, some of the lappets are missing. These asteropyginae trilobites are far more delicate with thinner cuticle than the Eldredgeops rana, and so are more prone to disarticulation due to hydrodynamic forces
Two prones. The one one the left will be an easy prep. The one on the right was Deb's first in the field repair. She had accidentally flicked off the piece (shown with the whitish residue of cyanoacrylate) and I miraculously pulled it out as the first shard from the muddy, opaque water where it fell! It has not been reattached incorrectly; it has become disarticulated at the fourth pleural segment, possibly on account of compaction (which has also flattened it).
Two semi-prones. The one on the left is missing a bit of the glabella.
Assortment of rollers and semi-prones. Unless the rollers appear as more than one in the matrix, I tend to free them from their shale confines.
Although the split sheared the cuticle, I kept this complete roller on account of the large calcite grains in evidence.
Another full, albeit small, prone to prep. On the right is what remains of the throrax of the rare Bellacartwrightia sp.
In all, not a bad few days, but far from my best haul from this location. Gregarious trilobite assemblages were not much in the offing as we chased through the slabs for pulses in the Smoke's Creek layer of the Windom, coming up with a lot of very dense, blank or mostly coral-littered shale with no apparent bedding planes. Without the latter, it becomes mostly guess-work and luck with the hammer to bash the slabs open at the right spot.
My next post will follow the process of preparing my largest bug from this dig, and then it's off to Bowmanville for the biannual Ordovician quarry visit in search of Isotelus and Ceraurus.