Saturday, April 17, 2021

Winter Whale excavation, part 4: the grand finale, and the future

 The dramatic conclusion of our midwinter basilosaurid whale excavation in Harleyville, South Carolina! [warning: this post is PG-13 as there is some light but accurately portrayed language]

See Part 1 here.

See Part 2 here.

See Part 3 here.

A behemoth sized front loader approaching our jacket. It looks small here but it's still almost 20 feet away....

Day Six  – calling in the big guns

We returned for a fourth full day of digging (day five including the first afternoon out), and Rich had already made arrangements with the mine to use some of the heavy equipment. I knew that we would have a big crew (in addition to Rich, Sarah, Scott Persons, and myself) – Ashby joined us again, the Basaks showed up, along with Mark Bunce, Everett White, and Alex Mertz, Matt Gibson from Charleston Museum, and I had also invited local collectors and donors Michael Wayne Musick and Laurel Black to join us for the first time. Departmental colleague Dr. Scott Harris came along for an occasional heavy lift and also to survey the strata - quarries are unparalleled opportunities to do so, after all. A few days before I had authorized a documentary crew that had recently materialized, within the past week – ostensibly working on a documentary about amateur fossil diggers here in Charleston – to join us for the big jacket removal. Nevertheless, I wasn’t expecting a crowd of about 25 people to be there – about 8 or 9 faces, some of whom were involved in the documentary, I did not recognize. Whatever, extra hands, right? As the film crew went about collecting release signatures, I realized we were now about 30 minutes behind schedule and I was beginning to get a bit frustrated with the circus that had blossomed in the parking lot. We finally got into the mine, but about 45 minutes after I had hoped.

The ginormous front loader bucket really did much to minimize our efforts! Here Scott and I are discussing how best to lift it. One of our flat straps had broken (which did not bode well, to be honest). Photo credit: Sarah Boessenecker.

We trudged up the hill towards the pit, and I noticed immediately that a relatively humongous mine tractor (front loader/quarry ripper to be specific)- easily the size of my house, and I’m not kidding when I say the top of the vehicle was two stories tall – was crawling up the slope to our whale. I tend to get a little overwhelmed by such things and thought “wow we’re doing this already, in the first 10 minutes of the day?” As we’ll see in a bit, it was good to get a leg up on this part early on. We started with the two smaller jackets: five of us lugged the medium sized jacket over to the ‘bucket’ of the front loader. This jacket was only like four feet long, and the bucket of the front loader was like 8 feet deep and 15 feet wide. For the large jacket, we needed about 7 or 8 able bodied folks – myself, our preparator Shelley, and a bunch of others – and we used flat straps underneath it and a bunch just grabbing the sides/bottom of the jacket. We moved it a few feet at a time, and tucked it into the bucket. This ~5-6 foot long plaster jacket – the largest I’d ever excavated – was dwarfed by the comically huge tractor. It felt sort of unnecessary – and then I remembered that at a quarry, they generally don’t bother with using any small machinery owing to the volume of earth they push around (a train literally backs up to the plant to pick up cement aggregate). Mines are all about efficiency, and this tractor was diverted from quarrying from only a few hundred yards away.


This looks very well choreographed and balanced but we really needed one more person on the right side as that end just dragged. Oh well, we didn't repeat the mistake later on! Photo credit: Sarah Boessenecker.

And just when I thought our plaster jackets couldn't look any smaller, placing them inside the bucket accomplished exactly that. Photo credit: Sarah Boessenecker.

The front loaded backing down the hill towards the vehicles with our precious (and dwarfed) cargo. Photo credit: Sarah Boessenecker.

The tractor backed slowly down the hill, and several volunteers were helpfully and cheerfully competing for the right to transport the jacket in their pickup to the museum downtown – in the end, Josh Basak won out, and the tractor, about 10 times larger than his truck, approached the tailgate (the bucket of the tractor was basically the same size as the truck, and probably heavier). The tractor driver was a real artist – he approached the truck, and managed to, from 15 feet up in the ‘cockpit’, delicately lower the bucket until it was no more than 6” above the tailgate - and really above it – no gap, and I could see Josh tense up and ready to yell if that bucket slammed down and knocked the tailgate right off its hinges. But, that didn’t happen. I hopped in the bucket to take in the sight and develop a plan – and the mine safety officer said “nobody can be in the bucket”. I thought “fuck.” I probably said it too, to be honest. You see, the problem is that the bucket is about 4-5 feet off the ground, a very awkward height to lift anything at – and something that big will crush you if it falls. The jacket is also like nearly as wide as the pickup bed – meaning there wasn’t really anywhere to stand except for on the ground or where the jacket was supposed to go. So, I had a couple guys get on the ground and we slung one flatstrap under the lighter triangular “nose” end, and myself and one other – definitely the two scrawniest of the bunch – would pull on those. The bigger guys would have another flat strap looped around the back, pulling it forward into the truck – and a couple of guys on the ground lifting up to reduce friction. It worked a lot better than I anticipated, and everyone kept all their fingers and no bruises were awarded. I glanced over and saw that Mark Bunce – the collector who had found the specimen – was looking pretty teary-eyed. I congratulated him, and we got some pictures of the jackets in the back of the truck.

The enormous front loader approaching Josh's truck. Photo Credit: Matt Gibson.

The jackets offloaded into the bed of the truck. There wasn't much empty space in there!

The gigantic, and now empty, bucket of the front loader ominously hanging over the truck.

Now, we still had some fossils in the ground, and some in the truck – we had to split up into two crews: one crew that would stay at the quarry and work in shifts (in theory) and another that would head downtown to drop off the jackets. I was very relieved to hear that our curator, Dr. Scott Persons, had offered to lead the effort downtown if Sarah and I would lead the excavation effort. Great! But, easier said than done. After the highlight of the day, it seemed as though we splinted into three factions: Scott, and one or two others, the digging crew, and a third group of volunteers who had disappeared off to a different part of the quarry to dig for shark teeth. This was pretty frustrating, as we continued digging – at a slower than expected pace – because many folks who had gone over to the other part of the quarry had not helped at all with the excavation, and by 1pm, we 1) had not gotten even 1/3 of the way done with remaining jackets and 2) had not rounded up a group of volunteers to head downtown. This was starting to piss me off a little bit. I, and one other, walked over to wear the shark tooth diggers were, and asked for help – and there weren’t really any willing volunteers. This was a bit frustrating, since I had explained at the beginning of the day “we need to be working in shifts on the excavation, and if you want to head over to the shark tooth spot for 15-20 minutes, great! Just come back to relieve someone else.” This basically wasn’t happening – and the frustrating part was that they were all out here at my invitation. After two hours of nonstop chiseling and picking, none of us had been able to take a break. I politely explained some of this, and got a couple of volunteers: the rest, I put on a mental checklist of folks who would not be invited back on one of our collecting trips. [Some had indeed helped lift the jackets, but this only took about 10 minutes total].

Ashby Gale showing me an enormous phosphate nodule he had found at the alternate dig site where everyone was finding big shark teeth - after nobody else volunteered, Ashby gave me an exasperated look of disbelief and volunteered. "A bunch of dirt just collapsed in my hole anyway!" I felt bad, since Ashby had worked so damn hard he hadn't gotten a break at all, and others had volunteered perhaps 20 minutes of their time - but could not be dissuaded from their precious shark teeth.

On the flipside, Scott was having a hell of a time getting anyone to commit to heading downtown; he finally managed to arrange for a group of about 8 or 9 volunteers to meet him at the building. They managed to get the jacket into the building safely, though I don’t want to even imagine what it was like after participating in moving it into and out of the tractor earlier in the day.

The scatter of bone (and molar) that Shelley Copeland had accidentally uncovered turned out to be the left mandible, oriented parallel with the axis of the upper trench we had dug – now the wall of a massive 3 foot deep hole the size of a king size mattress. We started digging behind it, and uncovered a vertebra – and the pedestal, which I imagined would just be a 3 x 1.5 foot cylinder – had now ballooned into a 3 x 3 foot square and about 18” thick on one side, so perhaps a 150 lb block. This was unacceptable: I knew that we could get the trenches closer to the mandible, so I directed others to start trimming closer and closer – carving in a line to aim for with the expanded trenches. On the other side, Sarah and Ashby Gale had been diligently working on a cluster of vertebrae near where “Rich’s Lumps” were – a 2.5x2 foot block of limestone. They kept on hitting bone, but also found a deep trench filled with soft matrix and bone fragments – the groove from a quarry ripper. I had estimated that the quarry ripper blades were spaced out about 4-6 feet on the tractor: these are lowered below the tractor tracks, and the tractor drags these, much like a 3-clawed tilling tool used by a gardener, to loosen the upper 1-2 feet of limestone, which is then pushed around by the front loader end of the tractor; eventually an excavator (think of a steam shovel) will load the rock into a giant dump truck. That’s as complicated as limestone mining gets. I wondered how many more deep grooves cut right through our fossil, and shuddered a little bit: that will be a disappointment for a future version of me, and a decided not to think about it. This groove basically cut a trench for us, which was convenient – we now just needed a trench around the rest of this patch. They kept hitting bones – mostly vertebrae and vertebral epiphyses – which I chiseled out, bagged up, and encouraged them to pick the pace up a little bit.

The somewhat terrifying quarry ripper on the other end of the front-loader: when engaged, these huge blades rip off blocks of the upper 1-3 feet of the limestone, which is just too hard to be scraped through directly. Our whale is certain to have at least two of these big trenches cut right through it - though now that I'm seeing how spaced apart they are, we may have gotten away very lucky. Photo credit: Sarah Boessenecker.

Meanwhile, the mandible jacket was coming along well – and a trench had been dug between the mandible and the vertebra back in the wall, so I took over – confident the trench was below the bone level – and dug it much faster with a big pick. Since I was in charge and happy with failure, I took the responsibility of swinging a bit fast and loud – I’ve also had quite a bit of practice and am a bit of an artist with the big Estwing pick, so it helped speed up things. Also, bending over and chiseling was killing my back; I had had moderate lower back pain since October and this whale did not help matters. So I opted to let others do the detail work with chisels and bang through a bunch of overburden with the pick when necessary/possible. Schuyler Basak offered to cut out the vertebra behind the jacket with the Sawzall – but not before I gingerly covered up a large premolar that had been uncovered next to the mandible. I wasn’t sure if it was an upper or a lower – but it was hollow, with only 2mm thick enamel/dentine in the crown – meaning that these were probably adult teeth in the process of development, which is extremely exciting. Schuyler quickly sawed out that vertebra, and I immediately began to dig out the fossil-free void behind the mandible block to allow for jacketing of the mandible. We took turns rapidly trimming the pedestal, and it was mostly undercut on all sides when Rich informed us, that owing to a planning snafu, the mine safety officer needed to leave at 3pm and we all needed to leave. I asked for another 20 minutes – which we were granted – and we hurriedly slapped on a plaster jacket over the mandible to keep it protected. It was mid December, and I had no idea when we were going to be allowed back – this was a surprise, and admittedly frustrating, but I was assured the mine had no intention of disturbing the site. We managed to get everything protected for when we would return.

Josh Basak using the sawzall on the block containing the left mandible. This was a nice little jacket, and honestly, the size of the jacket I thought we'd be taking out with us on the very first day.

Day Seven  – that’s a wrap!

Aside from a drive up to the mine a few days before Christmas when we found out everyone who’d help us was gone on vacation and we had to just go home, we managed to get back into the mine a month later in mid January to finish the excavation. We had a much smaller crew this time. When we arrived at the excavation pit, we noticed a hole cut into the plaster near the end of the mandible: disappointing, and very clearly picked open by someone. We had heard secondhand stories of some shark tooth crazed collectors who were crazy enough to sneak into the mine – and gotten caught. This led some credence to those. I doubted anyone from the mine would have done that. Regardless, my biggest fear would be that trespassers would have come in and vandalized it more seriously, but they didn’t; we patched up the hole with some plaster and quickly got to work. Within an hour had trimmed the mandible block and put more of a jacket below the undercut. By noon, the Basaks had used the Sawzall and undercut the mandible jacket, and we removed, flipped, and jacketed the other side after some trimming – I again cut a grid into the bottom and we chiseled out little limestone cubes.

Ashby Gale working on clusters of bones found around the small square vertebra jacket.

More digging of this stubborn little bone cluster.

Sarah and Ashby working on the stubborn bone cluster, which had a high wall next to it (what Sarah is sitting on); another challenge were the ever present scatter of small postcranial elements (vertebrae, ribs, vertebral epiphyses).

The vertebra jacket was now trenched, and so we slapped on a plaster jacket. There were several ribs and vertebrae opposite the trench – we started to uncover those, and began to make some small pedestals destined for smaller simple plaster cap jackets. One of these developed a crack, and was then subsequently dropped – and could be in better shape, but oh well – it’s fortunately just vertebrae. Still, though, we were burning daylight: we were still an hour away from getting the second medium sized jacket out, and the small clusters around it, and someone lad discovered more bone above it in the wall. After another hour or so it was no 4pm and the sun was getting low on the horizon – and we used the Sawzall to undercut the second square shaped jacket with vertebrae inside. Within another half hour we had applied small tin foil or plaster cap jackets to remaining bones around it. Schuyler busted out the Sawzall one more time to remove one of the bones stuck in the wall – possibly a vertebra. I, very stupidly walked over to take a look – and the saw slipped out of the cut and splattered limestone grit all over my face, including my mouth, and worse – my left eye. When I inevitably closed it a millisecond after impact all I could feel was grit and my eyelid not closing completely – and a sharp stabbing pain. It was admittedly not as painful as the time a stray drop of plaster splattered up into my right eye during a dolphin excavation on the California coast five years before – but it still hurt really, really fucking bad. 

Now, when I’ve had a moderate injury I tend to just get mad and the typical string of cuss words leaves my face, but when its something serious, I tend to just focus and rationalize my way through it – and ignore everyone while I search for a solution. I didn’t want any help, so I stumbled over to my backpack, fished out my water bottle, laid down in the mud, and began gingerly pouring freshwater into my eye and brushing out the grit. [apparently all work ceased and the rest of the crew was just watching me, which I was unaware of, and it was my sincerest intention that they just get back to work]. After about a half gallon of water and 15 minutes of effort, I couldn’t feel any more grit – though my eye was so fucked up, I had no idea that there was still a 3mm long sliver of limestone below my lower eyelid. Feeling substantially better, I picked up an estwing pick and approached the pit. I was met with skeptical facial expressions: I recalled that scene in Return of the Jedi where our heroes are in the middle of escaping their execution by Jabba the Hutt on the desert planet Tatooine, and Han Solo aims a blaster pistol at a tentacle on Lando’s leg – Lando exclaiming “I thought you were blind!” and Han responds “it’s alright I can see a lot better now!” Well, let’s just say I didn’t blame them for their skepticism, though they gave me an extra foot or two of safe distance. By sundown, we managed to get everything out, and down the hill – the last bits of our whale skeleton, and unbeknownst to me, a 3mm long sliver of limestone I discovered after I got back to the car and looked in the driver visor mirror. After a few more attempts to wash it out, I thought, good enough! And we drove home. An hour later I realized it was STILL IN THERE and after another 15 minutes it finally was flushed out – and made a “ting” sound when it landed in the sink. My vision was quite blurry for about 24 hours but after it returned crystal clear, I decided against going to an eye doctor in the middle of a pandemic since it wasn’t necessary.

The jacket containing the left mandible, fully finished! This will likely be one of our first jackets we open up.

Veteran collector Mark Bunce sitting in the middle of this gigantic hole that once served as the burial place of a very interesting little archaeocete whale.


A full week, spread out over two months, and the efforts of about 20 people with the assistance of the Giant Cement Mine itself culminated in the successful excavation of one of the more complete skeletons of a basilosaurid whale found in the southeastern USA. This specimen includes at least parts of the skull, left and right mandibles, much of the dentition (at least half of the teeth), periotic and bulla (earbones), cervical and thoracic vertebrae, ribs, and some postcranial bones. I am hoping a pelvis is hiding in one of the jackets, though we didn’t encounter any obvious lumbar or caudal vertebrae, so this is wishful thinking. What can this whale tell us?

1)    The identity will be critical: it is possibly Chrysocetus healyorum – or possibly Dorudon serratus. Both are poorly known and the holotype specimens are based on juvenile specimens.

2)    Expanding the known anatomy of one of these two species – or, doubtfully, it may be a new species. It’s more likely one of the two. If it is, it will at minimum significantly expand the anatomical knowledge of Chrysocetus healyorum – the first earbones for the taxon, first complete mandibles, and whatever skull parts are preserved are guaranteed to be significant as well. If Dorudon serratus, even better – the holotype is a shattered skull known only from a few teeth and indifferently preserved skull fragments. This would dramatically expand the known record of Dorudon serratus.

The holotype teeth, braincase, and pelvis of Chrysocetus healyorum - a small basilosaurid whale and the earliest case of monophyodonty in Cetacea? [From Uhen, 2013: Review of North American Basilosauridae: Bulletin of the Alabama Museum of Natural History 31:2:1-45).

3)      Chrysocetus healyorum was interpreted as a juvenile with unusually early occurring permanent teeth – at a similar stage of development, Dorudon atrox still has milk teeth – so it was proposed to be the earliest monophyodont cetacean: the first whale to only develop a single set of teeth. So far as we can tell, all Neoceti are monophyodont (or, at least dolphins are; right whales show some in utero evidence of diphyodonty, but only in the lower teeth). This specimen will likely shed serious light on this question, if indeed it represents Chrysocetus: the teeth are hollow and incompletely developed (indicating very young ontogenetic age), so this specimen is guaranteed to be a nice window into the growth and development of early cetaceans. Will we find a mix of adult and milk teeth? Or something more surprising?

Two slightly different interpetations of the exploded skull of Dorudon serratus: Top - True, 1908 (Bulletin of the Museum of Comparative Zoology, V. 52); bottom - Kellogg, 1936 (Carnegie Institution of Washington Special Publication 482).

4)    Potentially unexpected but surprising adaptations. This falls into the “unknown unknowns” of the Donald Rumsfeld three-stage division of knowledge (1, 2, and 3 being “known unknowns”). For example, Ancalecetus simonsi, a small basilosaurid whale (with otherwise normal looking skull & dentition) from Wadi al Hitan, had bizarre scapulae, thickened forelimb bones, and fused left and right elbows with the elbow joint strongly flexed rather than straight out like a normal flipper – leading the authors to speculate that it may not have used its flippers in swimming at all. Some weird feature like this could always be waiting for us inside the jacket.

We also collected some interesting associated specimens, including some rare Eocene bird bones and one of the geochronologically last boxfish specimens before the End-Eocene climate crash – an indication of the last period of tropical/subtropical marine climate in the region for quite a while.

Many thanks to all of those who helped: all the local collectors, fellow museum workers/geology faculty - and of course, thanks to the mine for letting us do this excavation and to the mine contractors who helped us move these plaster jackets.

Sunday, April 11, 2021

Winter Whale Excavation, part 3: making, flipping, and moving some uncomfortably large jackets

See Part 1 here.

See Part 2 here.

See Part 4 here.

Day Four – finally some real progress

We took over a week off this time and returned with a larger crew, with the capability of flipping the block over. The normal museum crew consisting of myself, Sarah, our curator Scott, and preparator Shelley had come out, joined by Ashby Gale Schuyler and Josh Basak also joined us – they, and Mark Bunce, had indicated they could use a reciprocating saw to help speed up the excavation. I was skeptical of anything battery powered; my own battery powered drill conks out after about an hour of use, after all. I shelved it for the time being – besides, the priority was to dig the trench deeper, and then we could talk about power tools. We spent a couple of hours deepening the trenches – using the estwing ‘super pick’ to remove large blocks of limestone about 3-4 lbs in weight, and then someone on standby with a shovel would remove them while the picker took a breather for a minute – and then repeat. An issue we were quickly finding to be a problem was drainage: the upper 2-4” of the ramp was lose mud rather than bedrock. Because the bedrock was impermeable, the water would flow at the bottom of this loose mud layer rather than on top. Further complicating this was that this was continuously trickling into the trenches we were digging. On the second day, we had dug a trench around the entire pit, thinking that if we dug down deep enough we could channel all the water in a circle around the pit. It definitely helped – the pit didn’t fill up enough – but it took a good half hour of picking to make that trench. And, after another hour, our trenches began to fill again – albeit at a slower rate. This time, we decided to systematically excavate the trenches so that water would flow downhill rather than pool up in the trench. I also spent the first hour undercutting and popping out Rich’s two jackets, which came out without incident.

Back to work on the blocks: our trenches are approaching the lower limit of the bones, which would mark a turning point in the excavation. From left to right: Sarah Boessenecker, Scott Persons, Shelley Copeland, I'm at the bottom in blue hardhat, and Josh Basak's arm off to the right. Below Shelley are "Rich's lumps", which we removed within an hour of taking this photo.

The second largest block (housing mostly cervical and thoracic vertebrae, and ribs) after flipping - being trimmed by Curator Scott Persons. A major gamble here was how many or how few bones were in the trench between these two blocks: fortunately when it flipped over all we could see were a couple of ribs in the fracture.

This gorgeous tooth of the Eocene mako shark Isurus praecursor was found sticking out of the limestone on the underside of the second largest block! I tapped it out with a chisel.

Scott (right) and I (left) continuing work on the two largest jackets. Note how much deeper the trench is compared to the first photo in this post above.

By about 1pm, we had come close enough on the second largest block to undercut it. We began undercutting with chisels, and then Josh offered to use the saw – I was skeptical until I saw how quickly it cut through the limestone. After some undercutting, we put on one more rim of plaster to get a skirt under the undercut parts of the block – this would help prevent cracking of the block during flipping. Once the plaster was cured, Josh began undercutting the secondary block by first using a drill (again, battery operated) with a 12” long, ½” wide masonry bit to drill a series of radial holes underneath the block. These were all in the same plane. Once this was done, he used the hole to allow the Sawzall to be stuck into the rock a few inches, and then connected up the holes into a single long saw cut – remarkable! He then made a second row of drill holes about 2-3” below the first, and repeated the sawing process. A few vertical cuts, and we were able to pick out the horizontal slices of rock. Now that these slabs were removed, the pedestal under the block was only about a foot wide or so – and there was enough space to fit the sawzall in again. One more cut was made, and then a series of large stakes – not suitable for chiseling but fine for cracking pedestals – were hammered in carefully into the pedestal. The jacket was freed relatively quick – it took about three of us to flip it and four to move it up onto the rim of the excavation pit, which now had significantly more free space. This jacket was just shy of 3x4 feet and about 10-12” thick – and probably weighed about 150 to 200 lbs or so. Our difficulty in moving this block was starting to give me serious concerns about the large block. While we were clearly not going to flip the largest block, we were close – and we quickly continued to undercut the big block. By 4:45 or so we had removed three jackets, with the big one remaining. We would need to return, with probably at least two more days budgeted. Rich indicated that he discussed the excavation with the mine, and some of the mining contractors would probably be able to help us remove the big block – thank god, because that behemoth was going to weigh in excess of three or four hundred pounds.

The quarry wall, perhaps 50 yards away from the dig. The resistant rock is mostly the Tupelo Bay Formation; the overlying Parkers Ferry Fm., which is yellowish, has been scraped away and dumped elsewhere - along with the highly fossiliferous (but thin and patchy) Harleyville Formation.

Someone had gone off and found this spot a couple hundred yards away that was a post-Eocene (likely Pleistocene, in my opinion) bonebed above the hard matrix with large concretions and loads of shark teeth - chiefly Carcharocles auriculatus, like this nice specimen. This secondary site would later cause some complications.

The first few hours of Day 5 were spent digging down at a faster rate than we could before, by virtue of being completely below the bone-bearing layer. Dr. Scott Persons clears debris from the downhill trench, and Ashby is starting to uncover Shelley's bone & tooth cluster on the high side.

Sarah supervises while Ashby (left) and Dr. Persons (right) deepen the high side trench and clean up Shelley's bone cluster.

Day Five - flipping the big block

We returned again with a larger crew in order to get the big jacket undercut and flipped. In addition to the crew from the prior week, we now had Alex Mertz and Everett White – two large guys, and Jordy Taylor, a powerlifter – to help us out. In addition, we were also accompanied by two of our colleagues at Charleston Museum: Curator of Natural History Matt Gibson (a paleontologist/paleocetologist by training), and Natural History Collections Manager Jessie Peragine (a botanist by training, but working extensively with fossils by this point). We arrived, headed up the hill, and began trenching to get rid of ponded water, and to allow enough space for the Sawzall to be used. I had serious reservations about the thickness of this jacket – up to 14” in places – and its mobility. We would really need to trim it down after flipping to get it down to a remotely manageable weight. Regardless, we used pick, chisel, and the Sawzall to undercut the big jacket. After about an hour of work, there was perhaps an 18” wide rectangular pedestal underneath the approximately 5x4” jacket. Unbeknownst to us, one side was more extremely undercut than the other. After about only 10 minutes of undercutting with the saw, Josh started using the drill and just making a series of criss-crossed boreholes under the jacket, turning the rock into swiss cheese. Before we could even use a chisel to “pop” the jacket, we noticed the entire jacket was vibrating – this is a milestone in a jacket excavation as it means the block is now more likely to behave as an isolated block than as a pedestal still very much attached to the earth, but that you’ve given a cute plaster ‘hat’. The vibrations also mean you’re very close to being able to crack the block – normally using a series of chisels and a crow bar if necessary. However, Josh’s drill method was enough to do the trick – and owing to the lopsided trenching effort, the block “self-popped” – a perfect horizontal fracture ran right through the base of the pedestal! 

Ashby (top), Schuyler (left), and Josh (right) undercutting the big block, using hammer/chisel, masonry drill, and a sawzall (Josh is using one of two sawzalls, the other is in the foreground).

I even got some practice with the sawzall. What a fantastic tool! I was sold on this thing for the purpose of excavations.

One of our attempts in sliding the jacket up and out of the pit. Those two 2x4s used to be part of Ashby's house, and one of them broke immediately, sending me into a much needed fit of laughter during the most stressful part of an excavation. After about 10-15 minutes of jockeying we managed to slide it, a few inches to a foot at a time, up and out of the pit.

The entire crew tiredly relaxing and celebrating for a few minutes! Back row, from left to right: Matt Gibson, Everett White, Alex Mertz, Ashby Gale, Scott Persons, Schuyler Basak, Josh Basak, Rich Familia; foreground: Jessie Peragine, Mark Bunce, Sarah Boessenecker (on jacket), and yours truly (in recline; I almost passed out and took a nap in the mud).

A few minutes later we gathered up everyone, and got a couple of flat straps ready, and a couple of old wooden 2x4s to use as a ramp – though I had my doubts, as the wood was quite old. The block flipped quite readily, and immediately snapped one of the two 2x4s in half – I was captured on video laughing my ass off at this. After a few more minutes of straining, we managed to slide the jacket up and out of the pit with about six people – not encouraging, given how much effort it took. But, I was confident we could reduce the weight of the block by at least 25%. At this point it was 3:30 and getting cool – and, worse, several folks had to take off early. Schuyler, Josh, and I took turns using the Sawzall – we first trimmed off excess plaster, and then cut a grid into the top of the jacket: each cut was about 3” deep, and 3” apart, making for small cubes of sandy limestone that could easily be chiseled off with 2-3 taps of a hammer. We borrowed the Sawzall from Schuyler when she and Josh left, and we managed to cut in two more grid layers – removing about 8-10” from the jacket, before we found bone – and we knew we had to stop cutting. Within the next hour, as the sun went down, we jacketed the top (formerly the bottom) and completed that jacket. On our next return, we were set up well to remove the three largest blocks with help from the mine.

The mood may have been celebratory, but it was getting late, and we absolutely needed to complete the jacket. That required serious trimming. Make a jacket too much of a thin pancake shape prior to flipping and you risk cracking it: less risky to make it thicker, and just trim the hell out of it after flipping. So, we used the two sawzalls to cut a grid  3" deep into the limestone. Schuyler on the left, myself on the right. This tandem grid cutting ended up working like a very loud and very muddy ballet.

The sawzall takes a lot of effort to cut, and tends to turn your arms to jelly, so it was nice to trade off: Dr. Persons is now sawing, and the rest of us are popping off limestone cubes with hammer and chisel.

More chiseling. Here I am checking the underside for bone. I decided we would keep lowering the grid until we exposed bone: the minimum thickness of the block. We ended up trimming perhaps 8-10 inches of limestone, which is the equivalent volume/weight of the second to largest jacket. Jesus H Christ, the fisheye lens effect is not doing great things for my self esteem here... Me (left), Scott (behind my head), Jessie (green hardhat), and Ashby on right.

We got the top jacket finished just around 5pm - you can see there are no longer any shadows - whereas the prior photo, maybe 20 minutes earlier - was taken during the brief "golden hour". The sun is now behind the trees and it's starting to cool off a bit. Ashby on left, Matt Gibson on right.

All done! That doesn't look so bad, what was all the fuss about? Until you remember those are 2x4s...

We now had a three foot deep (~1 meter) pit the size of a king size mattress. Here is Josh Basak, surveying the crater. Nature abhors a vaccuum, and some blocks that had gotten in the way ended up back in the pit. We'd have to dig these out again upon our return.

Sunday, March 28, 2021

Winter Whale Excavation, part 2: day 2 [ctnd] and day 3 - panic and progress

 I wrote this a couple of months ago, but as usual, the spring semester got ahead of us! Here's the second installment covering our whale excavation this past winter. There will be two more installments and I'll try not to let them be spaced out quite so much!

See part 1 here.

See part 3 here.

See part 4 here.

Day two, continued: Panic and decision making in the field

When it comes to finding bone while digging – I’d rather have a clean break from removing a large block than something being chiseled through. One of the challenges we faced is that the bone at this excavation was so porous that it tended to just crumble when you got close to it – which is why Sarah exposed so much of the mandible using only a toothbrush. We didn’t have time to be so painstakingly slow, so we opted to find the edges of the bone scatter and just start trenching – digging blind, so to speak.


Sarah Boessenecker (left) and former preparator Shelley Copeland (right trenching, and attempting to find the edges of the bone scatter. Little did we know that more bones and teeth would be found to the right of Shelley's position and several feet behind her near that trench.

What are the advantages of “field prep”? You leave the field knowing precisely what you’ve found, and on a more important level, have much less to carry out in terms of mass: there is less rock in each field jacket. The disadvantages, I believe, outweigh these advantages – at least in my own experience. The first is time. I’ve always been in charge of or a party to relatively poorly funded field programs (dinosaurs tend to get all the big bucks, sadly) – none of which have the time to painstakingly excavate a skeleton in situ for weeks. We, on average, have perhaps 10% of the available time since we’re usually doing this on everyone’s day off (field trip leader included) or on an actual work day and avoiding teaching/grading/exam writing etc.

The "Fordyce method" of quickly excavating large fossils in soft limestone with students and power tools: 1) (upper left) have the young folks (students and preparator; undergrad Marcus Richards, left; preparator Sophie White, in green hat; Ph.D. student Felix Marx, right) carefully expose bone and uncover the edges of the bone scatter. 2) (upper right) - carve an outline about 2-3 feet away from the edges of the bone scatter - a 10-12" deep vertical cut with a chainsaw. 3) (lower left) Cut an inner cut, and a series of radial cuts that can be removed by students armed with picks. 4) (lower right) repeat this, going down one more layer, and then do an angled cut undercutting the block from all sides. We found this bone scatter at 9am, had the edges defined by noon, chainsawed by 3pm, and loaded up fully jacketed for the ride back to University of Otago by 5pm.

More power tools: the formidable, heavy, violent, but very effective Pionjar rock drill, here used on the South Otago coastline splitting apart large sandstone concretions. On left: Dr. Ewan Fordyce using the drill while then-Ph.D. student Yoshi Tanaka watches; right: then-PhD student Cheng-Hsiu Tsai (seated) and Ewan (in signature orange jumpsuit) use feathering wedges to split apart a thousand-pound concretion.

The advantages of finding the edges of a bone scatter and trenching ASAP is that you can quickly make a jacket by cutting out the time intensive ‘field prep’ stage – however, it does result in more and heavier jackets leaving the field, and requires more preparation (not an issue if the fossils are in relatively soft rock, anyway). In New Zealand, my experience in the Fordyce lab taught me the benefits of using power tools – we could dig up a 5 foot long jacket in about six hours or less, provided the whale (or penguin) was in the horizontal quarry floor – we would spend a couple hours finding the edge of the bone scatter, use a knife or chisel to mark the edges of the scatter – and the venerable Dr. Fordyce would take out a Stihl brand gas (er, petrol) powered chainsaw with a 3 foot blade and make three cuts: one vertical set of cuts at the edge of the bone scatter, another vertical cut about 12-16” out from that, and another cut 12” further out set off at an angle to make a wedge. The grad students would then spend about 15-20 minutes with picks to dislodge all of the sawn blocks. At the end of it, a relatively deep trench would be dug, and then the block would actually be undercut using the chainsaw rather than hours of painstaking – and back/neckache inducing – chiseling. Once undercut, we’d do one round of plastering, wait 20 minutes to cure, then proceed with chiseling – and in some cases, use the chainsaw again and literally just cut through the pedestal like a tree trunk. In one case we used the Pionjar rock drill – an incredible, but heavy, Swedish petrol-powered contraption that is a combination of a drill and jackhammer (and can be used as either) – it’s got a jackhammer bit that rotates about 30 degrees between each strike. After flipping the block, we often used a masonry saw to cut a grid into the excess rock from the base of the pedestal – which allows for quick removal of little 4x4” rock cubes, speeding up time otherwise spent on tiring chisel work by four or five times. On other occasions, we wheeled out a generator/air compressor into the quarry and used zip guns – basically like a giant airscribe (or, handheld jackhammer, for those of you unfamiliar with airscribes).

A typical assortment of tools - powered and otherwise - brought by Dr. Ewan Fordyce on a regular single day outing to quarries like Hakataramea Quarry, provided we knew we were going to be jacketing a whale. The chainsaw and associated gear is in the white tub on the left. Petrol powered masonry saw up in front, and petrol-powered compressor in back to power "zip guns".

The point of all this is that we didn’t have any of these tools available: we had hammers, chisels, picks, shovels, and whatever we could squeeze out of our muscles in a day’s work. By three in the afternoon, we were down to two people and had barely established a trench, and were no closer to having found the edges of the bone scatter. Worse, the sun was going down, and it was rapidly starting to cool off. I was rapidly becoming more and more anxious. Fortunately, the cavalry arrived: Ashby Gale swung by on his way back from Columbia and helped us pick up the pieces. I desperately needed a win – and I managed to isolate the periotic, and determined that there wasn’t much around it. I began to trench around it, and after about twenty minutes of careful – but nerve-wracking chiseling – I was able to remove a shoe-sized block of limestone, wrapped carefully in tin foil, that we were able to remove. By around 5pm, we had started mixing plaster- and we quickly applied three small plaster caps onto parts of the scatter, with the largest cap over the mandible to keep it protected. We also wrapped up the block of articulated (but fractured) thoracic vertebrae I “discovered” while picking with plaster. The temperature was, at this point, perhaps 55 degrees and rapidly dropping – and we plunged our hands into puddles of frigid muddy water in the quarry to clean off our hands. By 6pm it was 45 degrees and a light rain had started; we left the quarry chilled, soggy, overwhelmed and defeated – or at least I was. Retrieving the periotic was a small consolation prize.

The fruits of our labor from day 2: a few pitifully small plaster caps, and a small tin foil jacket with the earbone.

I thought a lot about this tactical defeat. Part of it, for sure, was going into it with a far too optimistic set of expectations – but also, my very first serious excavation where I was actually in charge: all of my excavations here in South Carolina have been small, one-day affairs – 2-4 hours to trench, undercut, and haul off blocks of limestone under 100 lbs. I’ve been in charge of smallish excavations that took several days in very difficult to access spots on the California coast – including the four-day long excavation of the Balaenoptera bertae holotype, a one day excavation with one assistant of a smallish plaster jacket containing a nice (and now published) skull of Parapontoporia, and a challenging two day excavation of a skull of Herpetocetus bramblei.

The last time I felt this overwhelmed was very likely June 2007 after trying to haul out a 150 lb jacket containing that Herpetocetus skull with my friend Chris Pirrone: we collected it ten feet above the beach and about 300 feet from the nearest route up the cliffs – a set of surfer’s “stairs”. Between the excavation site and the “stairs” were two small coves, the first filled with slippery boulders – which we began to navigate, but got blasted by a wave and dropped the jacket into the surf. I sat on a ledge at sundown, watching the incoming tide threaten the safety of the fossil (now entirely submerged), questioning my life choices, and wondering if the jacket would be recoverable at low tide tomorrow – and if the plaster would survive a night of tumbling in the surf. Chris encouraged me to continue, and we managed to wait for a gap between waves, grab the damp jacket, and approach a slippery rock ledge – and performed the second incredible feat of the evening: muscle this 150 lb jacket up an eight foot slope, covered in algae, without dropping the jacket, as waves were crashing down on our feet and legs. We had done it! The jacket was now out of the surf zone. Could we leave it over night? We were both cold and tired – but Chris, much like Samwise in Return of the King, encouraged me to press on.

The 2007 Herpetocetus dwarf baleen whale excavation: my second whale excavation. On left: me, at about 4pm, smiling like an utter dumbass, because I have no idea that the tide is coming in as quickly as it would and how unnecessarily difficult removing this tiny jacket would be. On right: removal of the jacket. 1) Location of the excavation, jacket flipped, finished, and cured by 6pm. 2) 6:30pm - jacket spends about 15 minutes underneath the Pacific Ocean while I evaluate my life choices. 3) 7:00pm, roughly: Chris and I, somehow, manage to carry jacket, now 50 lbs heavier thanks to waterlogging, up an 8 foot tall outcrop, the only one still accessible - as waves are crashing down on us, and we're waist deep in water, ankle deep between waves. 4) Roughly 8pm, after taking a bit of a breather and letting the jacket surface dry - we use a car mat to carry the jacket across this narrow ledge. The drop is about 8-12 feet, and there's now four-five feet of water down there. 5) 9-10pm: Chris and I manage to muscle the jacket with our last bits of rapidly fading strength, to lift the jacket up several shoulder to eye level surfer's stairs. Jacket in car by 10pm.

Our third impossible task was to navigate an 18” wide, 20 foot long ledge about 12 feet above the beach – now nearly high tide, so the water was about four feet deep here. This ledge was easily traversed with a surfboard or a regular field pack – but this jacket was nearly 30” across, and heavy enough that we would not have a free hand to steady ourselves. We would have to somehow get this jacket across in one shot without dropping it into the ocean or ourselves falling into the ocean. Chris went and grabbed the floor mat from his car – which we used as an impromptu stretcher, folding it up – we managed to shuffle across the ledge, ocean boiling below, without incident. Our fourth and final impossible task was to lift the jacket up the surfer’s stairs – in actuality a series of steps anywhere from two to five feet high. We managed several of the smaller steps, and failed several times on the final one – nearly at eye level, and getting the jacket 90% of the way there and then our muscles kept giving out. I finally proposed to put the flat side of the jacket vertical, and we would push it up and then into the wall when we needed to rest – inching it up a few inches at a time. We eventually got it to tip over the top – and let out victory cries! From there we used our last few shreds of remaining muscle fibers to lift the jacket into the back of my hatchback.

"I'd really like to go back to being a college professor". Funny at the time, entirely too relatable now. This marine crocodile was a similar situation: each time we went out, progress slowed more and more. Thermopolis Shale, south central Montana.

Now, that was a rough excavation: our defeat at Giant quarry was nothing in comparison. I had to remember that we had discovered – and not seriously damaged – a more complete specimen of Chrysocetus healeyorum – including the first earbones, good mandible, and periotic of the species (and only the second specimen). And, recovered the periotic. There was a lot of winning – but the rapid explosion in size of the fossil had really freaked me out. I was reminded of a seemingly never-ending excavation of a marine crocodile in September 2010 I had participated in – fellow master’s student Cathy Lash had discovered it in her field area in south Central Montana, and our adviser Dave Varricchio had offered to help excavate it. However, the shale became increasingly harder and more difficult to dig through – and one weekend became two weekends in the field, and it was approaching the end of September – and only half the skeleton had been uncovered. I recall Dave becoming increasingly frustrated, wanting help and commitment from Museum of the Rockies – and at one point said “I’d really like to get back to being a college professor”. I thought it was hilarious at the time – and I had lost research time for my own thesis and felt similarly – but now as a young professor and with a seemingly unending scatter of bone - I could really relate. [Eventually MOR sent a few people out to help the Earth Sciences Dept. field crew, and a few years later, the specimen was completely prepared and was out on display when we returned to Montana after our time in New Zealand].

Other concerns weighing on my mind were weather and quarry operations. We had found out that the mine would not be continuing mining activities on that ramp for about two months – which was admittedly plenty of time, enough time to ask if volunteers could dedicate about one day a week. With volunteers – people who have jobs they’re taking time away from to help us out – you’re simply not going to have several days commitment back to back. Nor could I actually afford that much time away from my own job. The benefits to spreading out collecting over many weeks are several: it keeps everyone fresh – myself included, as I went into this with an already mildly thrown out back – and keeps everyone from being burnt out. It also allows for some rain in between trips and gives the volunteers some nice fossils to go out and look for when they’re taking breaks – a good incentive since most collectors don’t have access to Eocene rocks in the area since they’re all in quarries, like Giant. However, it is winter now, and while December is not much colder than November, January and February are quite cold here – not as cold as our time in Montana, but certainly much colder than California.


Tabytha Wall's makeshift office in the back of Ashby's truck: she came out to help when we needed all hands on deck, but was saddled with a grant proposal deadline. I thought this was way too funny not to share.

Back to work on the bone scatter: Shelley working on the high side of the pit.

Day Three - inching closer and closer

We returned the following Sunday with a slightly larger crew – Sarah, myself, Ashby Gale and his fiancée Tabytha Walls, CCNHM preparator Shelley Copeland, CCNHM curator Scott Persons, and Mark Bunce and Rich Familia. I returned guardedly optimistic – our major goal for the day was to finish trenching, apply a plaster jacket, and perhaps even flip the large block, and at minimum, remove some smaller blocks. We arrived slightly later – 10am – since the 9am day the week before was a bit on the early side, and it was still quite chilly. We lugged all the stuff up the hill and had a great morning – not much more bone was being found, and we were actually starting to excavate a bit of a trench. However, by 2 in the afternoon, I was beginning to realize that flipping the big block was not in the cards. Scott had to leave around 1pm or so, and Tabytha got screwed over at the office and needed to work in a makeshift office in the bed of Ashby’s truck to complete something a coworker failed to – so by 3pm we were back down to our skeleton crew again. I decided that at best we could define the margins of the jacket and apply a single top jacket on, and place the needed plaster caps onto the smaller pedestals. Rich had continued to work on his small pedestals – his “lumps” as we dubbed them – which contained some vertebrae. Late in the day, I started expanding the trench on the high side of the specimen and found another bone cluster – complete with a complete lower molar of our whale – but since all three lower right molars were in place in the jaw, this meant that it was a left lower molar. A few more mandible-looking fragments appeared, and we covered it up with some tin foil. By this time the sun was getting low, and we knew we needed to start getting ready to apply a plaster jacket. We used most of the remaining water up, and mixed nearly two whole 30lb bags of plaster – applying a large jacket over the main bone scatter, a patch on the newly uncovered tooth and bone scatter, and jacketed Rich’s two small pedestals. We were all done by about 4:30, and by 5:15 we had rinsed our hands off, put a tarp over the specimen, and packed everything back down the hill to the cars.

We left on Day 3 without any more jackets, but, hit a major milestone: our trenching around the main block had failed to find any further bones. This meant two things: 1) we could apply plaster jackets to everything, and 2) we could now dig downwards at a much faster and significantly more careless pace!

I regretted not having a tarp on day 2 (arrogant me thinking we'd have the few exposed bones excavated in a single day in a couple of small jackets) so we picked one up from Lowes, and covered the jacket with it and some rubble.