“I think you need to come and look at this again” called Dr Martin Lockley.
Dr Charles Helm, his wife Linda and myself were walking away from an overhang of aeolianite with a series of fossilized tracks on the under surface to look at another series of fossil tracks which Dr Helm describes as a work of art.
When an ichnologist and paleontologist as renowned as Dr Lockley says “I think you need to look at this”, you do. So we retraced our steps to the overhang, the sense of excitement tangible.
Preserved in time.
Patiently and methodically, Dr Charles Helm, an acclaimed ichnologist, has for the past decade walked over 275km of coastline between Witsand and Keurbooms river hunting fossilized tracks along the shore. He has discovered and identified numerous trackways. With a team of experts he has aged the fossil dunes and the sections where the footprints have been found and had compiled an impressive catalog of species, both extinct and extant, which lived along the coastline in the past 150,000 years.
Species identified include large spiders, field mice, birds (both wader and passerine), reptiles, canids, lions, extinct horses, zebra, giraffe, buffalo (both Cape Buffalo and extinct Longhorn Buffalo). Of the larger species, there are hippopotamus, rhino and elephant tracks. Literally hundreds of elephant tracks, if not thousands.
More recently, in the past two years, excitement has mounted as Dr Helm and his team have discovered, and published on human footprints as well as identifying possible human artwork and doodles in the sand. Lines and shapes that suggest a range of functions from artwork, foraging activity and possibly ritual communication.
Archaeological records in the Southern Cape document human activity extending 164,000 years back in time. Scattered in middens, cave sites and overhangs from Matjies River to Blombos Cave, are a collection of early, middle and late stone age tools, each era demonstrating an increasing level of sophistication. In cave 13B at Pinnacle Point, Dr Peter Nilssen describes how some rocks were even heat treated as part of the manufacture process of stone tool.
In Blombos Cave, news of the oldest Homo sapiens ‘art’ rippled through the world. Dated at 71,000 years BFC, the series of lines scratched into a piece of ochre were jokingly described as the first ever hashtag.
It has been well documented that modern humans roamed the region foraging from the intertidal zone. Called Strandlopers, it has been proposed that cognitive thought in modern humans developed as a result of the high phospholipid content of their diet. Research by Dr Jan de Vynk demonstrated that a mere 90 minutes of foraging in the southern Cape intertidal area yields more than the daily energetic requirement of an adult human and is the highest rate of calorific harvesting of any hunter gatherers in the world, followed by forest hunters in the Amazon and central Africa respectively.
Yet in all these remarkable archaeological sites of Strandlopers, there is scant evidence of the species of fauna that abounded during this remarkable development of our ancestors. From their middens we know that they had a varied diet of seafood mixed with some terrestrial faunal species, but there is a lack of a comprehensive account of which species were present.
Etched in Time.
In May, while hiking on the Strandloper Expedition between Blombos and Wilderness to document plastic pollution and fishing debris, we had the opportunity to scout for fossil trackways, hopeful of discovering new sites. And we did. Plenty of them, but we were unable to dedicate time to documenting them in detail.
It was at one set of elephant tracks that expedition member Melinda expressed her relief at the identification of the tracks. She had seen some impressions in the rock earlier and had thought that they were elephant tracks, but tempered by the caution and the seemingly incredible concept that there would be elephant tracks fossilized in the fossil dunes, she had not pointed them out.
The remarkable thing is that when you know how to look for fossil spoor and trackways in the aeolianite along the coastline, you start to see tracks everywhere.
Most of the spoor aren’t what you are accustomed to seeing when you walk along the dune or beach and see fresh tracks of birds, dogs and even antelope. Instead, with fossil tracks, you see undertracks, profile depressions, pedestal tracks and remaining infill. You have to view the potential track and visualize the mechanics of it being formed and then the process of them being preserved. Tracks are only exposed when the aeolianite has been eroded, so you also have to consider which plane you are viewing the track from, and in the case of a cliff collapse, if it is upside down, tilted or in the original orientation.
Personally, one of the most profound aspects of viewing a series of tracks is knowing that over the past 150,000 years the sea levels have fluctuated between 130m below and 13m above current levels. Yet, in all that time herds of animals have been traversing across what is now our coastline and even migrating along the shoreline. Then, the perfect conditions occurred to preserve the tracks, and now after the correct erosion they are again exposed. A chance of one in a million to be discovered.
At one site near Plettenberg Bay a vertical surface of 7m has no less than 9 surfaces of registered trackways, mostly elephants, viewed in profile. In short, for thousands of years, maybe even 10,000, herds of elephants were heading over what would have been a dune, a current day fossil archive of a potential migration route.
A week of discovery.
I first had the privilege of meeting Dr Helm in late 2018 at a fossil trackway presentation in Wilderness. The content was incredible, but most inspirational was that so many of his published work were from sections of beach that I have walked regularly between Wilderness and the western head of Knysna. I was quite literally blown away at how many I have walked past, almost on a monthly basis, for the past 15 years.
In November 2018, I was invited to accompany Dr Helm and his research team to collect a sample of aeolianite from a site near Plettenberg bay for dating purposes.
It is a remarkable site with Golden Mole, antelope, zebra, ungulates, Black Rhino and elephant tracks formed between 120,000 and 133,000 years ago. While the team collected their samples, inspired I scrambled across the fossil surface and found a set of tracks. Huge in dimension, they could only be one thing. Elephant.
They hadn’t been recorded, so we extended our visit to photograph and measure them and they have subsequently been documented as some of the largest elephant tracks in the region, an experience which ignited a new interest.
Living in Canada, Dr Helm returns to a holiday home in Great Brak for three months every year, so it was a great privilege when her mailed me to ask if I would be able to join him on a week of field trips during his 2019 visit when Dr Martin Lockley would accompany him to review some of the trackways described in published papers and papers under review.
A Moment in Motion.
As any tracker knows, the art of tracking is not only being able to recognize the spoor of a particular species, but being able to read the tracks to understand the activity of the animal as it passed on its way.
Pausing to check a few small impressions on a near vertical surface, Dr Lockley pointed out the fossil tracks of a running Field Mouse. Further on, in another pile of collapsed blocks of aeolianite, a series of regular lines came to life as Dr Lockley decribed the fast walk of a large spider.
Two surfaces of equid tracks captured the moment of an animal in full gallop and a canter or trot respectively.
Elsewhere, aquatic wading birds feeding in the muddy bed of a pan are preserved in three dimensions while 27cm deep elephant tracks record at least three individuals trudging through thick mud in a permanent pan, impressions that registered over years, possibly even decades.
In addition to containing records of extinct species, some tracks of extant species like giraffe and sea turtle hatchlings alluded to different climatic conditions and habitat approximately 120,000 years ago.
Retracing our steps.
It was a remarkable week of exploration along the length of our coastline between Plettenberg Bay and Stilbaai. Watching two master trackers of their caliber scrutinize each fossil impression with rigorous precision was mesmerizing. Not only do they understand the mechanics of a footprint registering on a surface of dune or beach, they have a wealth of experience knowing how it filled in over time, was weathered, then preserved and finally eroded to be exposed.
Taking into account the complicated circumstances which make the discovery of a trackway possible, adding the vagaries of the shifting beach sands which vary but 2.5m on average, and your odds of finding tracks are further reduced.
For our third field outing I arrived five minutes late for a beach walk to review a series of tracks. As I was walking fast to catch up with the team, I stumbled across a set of canid tracks. Well preserved, they were in a section of aeolianite which had recently been exposed by rough seas and was below the mid water level at low tide. The random chance and the ephemeral exposure aptly demonstrated the element of luck that is sometimes required to find some fossil tracks.
As I chased after the team, I noted an overhang with a busy trackway on the under surface that I hadn’t notice before. Making a note I continued and caught up with the team to check out a set of lion spoor. The object of this field trip was to evaluate a possible seal trackway. We arrived at the GPS location, circled around looking for it. Nothing. Nada! Just an expanse of beach
The weather was a mix of strong wind and drizzle that had blown in as Charles announced that the small rock peeping out of the sand was indeed the rock we were looking for. Kneeling down, we did what every kid does on a beach. We dug a large hole, only this was to expose the rock. One meter down and 2 meters across, we finally exposed the track, of a seal sliding up a dune with clear flipper marks where it had propelled itself forward. Mission accomplished.
Genesis of a Trackway
Now all we had to do was head back in the rain, check out the overhang and look at the canid tracks. But it was our own tracks that were fascinating. In less than 15 minutes the tracks had filled in. Driven by the wind and damp from the rain our spoor had filled in with fine sand on the leeward side of the registered impression and more course sand in the center section. Two densities making up the infill with the windward section of the track slightly open, for the moment at least. In particular, our tracks that were perpendicular to wind where now a narrow crescent of the outer windward edge of the track, unrecognizable as a human footprint at a casual glance. Dr Lockley explained, that to preserve the tracks, all that was required now was for them to be covered by a layer of sand and remain undisturbed while the process of lithogenesis fossilized them.
Reaching the overhang, Dr Helm had recorded it previously and pointed out that there were indeed two surfaces of the trackway, the upper ceiling with the protruding infill of the track and lying on the beach below it, the section which had fallen away to expose the tracks, and on its surface was the register surface of the original tracks. In one glance we had two views of the same tracks.
As Dr Helm was guiding me around a series of tumbled rocks to go view the ‘work of art’, Dr Lockley called out “I think you need to come and look at this again”.
Scrambling up to a vantage point, Dr Lockley started pointing out distinctive features that required evaluation. The length and pattern of the pace and any distinguishing features of the spoor needed to be measured. The gait and the mode of movement would need to be assessed an interigated to determine if it would be plausible that the tracks were bipedal, possibly homonin in origin. With a few more descriptions it became apparent that this site would require some extensive research before any conclusions could be confirmed.
In essence, a trackway of four tracks moving up a dune, one a smaller set, crossing from tracks of two larger spoor to join another track running parallel to the paired tracks.
Such a discovery, crammed into a week already overloaded with the confirmed identification of a range of fauna tracks, the discovery of locations of numerous more highlights the importance of rigorous research before these and similar surfaces with trackways are eroded away by wind and wave action.
Needless to say Dr C Helm et al have a busy few months ahead of them as they write everything up for publication, and they have only just begun scratching the surface of our heritage cast in the fossil dunes of the Southern Cape.