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]
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.
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.
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.
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.
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?
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.