Dinosaur Dreaming

2001 Expedition report

Lesley Kool

The discovery of the two best preserved mammal jaws ever found at the Dinosaur Dreaming site on December 3rd 2000, during the one-day field trip for the new volunteers, led to a last minute change of plans for the Dinosaur Dreaming 2001 field season. After the recovery of four mammal jaws among 1000 other fossil bones and teeth during the previous field season, we were keen to continue where we left off, approximately five metres east of where the one-day excavation was situated.

However, when Tom Rich returned from Japan in early January 2001 and was able to examine the two new jaws he suggested that we consider expanding the one-day excavation in the hope of finding more of the exquisitely preserved mammal material. One of those jaws has been beautifully reconstructed by artist Peter Trusler and appears on the front cover of this field report.

The decision to move the excavations further up the beach from where we originally planned was not a difficult one to make. As the excavations are all part of the same fossil layer, which extends from the intertidal zone on the shore platform into the cliff, it simply involved "leap-frogging" a five-metre section of the shore platform to excavate the targeted area.

The previous three field seasons involved excavating the eastern end of the fossil layer, situated up to 150 centimetres below the level of the shore platform. By the end of the 1997 field season it required approximately three hours labour each day to expose the site. As we only had an optimum three to four hours either side of low tide to extract the fossils, it became obvious that we needed to do something to shorten the site preparation period. Nick van Klaveren, the excavation manager, put his considerable talent for invention to work and created a system used to plug the excavation hole and prevent the bulk of the sand from being washed back into the excavations during high tide.

Over the next three field seasons this system was improved to a point where it was taking less than an hour to expose the site each day. But as the proposed 2001 excavation was higher up the beach and the fossil layer was closer to the surface of the shore platform, the system was not necessary.

The advantage of not having to put the system in place was not lost on the more experienced members of the crew. It meant that instead of spending four days at the start of the season drilling holes for the rock bolts and building sandbag walls, the crew only had to dig out the sand each day that had been washed into the excavation by the previous high tide. It took about an hour to remove the sand and wash down the fossil layer in readiness for the day's excavation. It also meant that we were able to work the site right up to the last day of the season instead of having to remove all evidence of the system in accordance with the permit issued by the Department of Natural Resources and Environment.

On the first day of the 2001 field season, Monday 22nd January, excavation of the new location at 185 metres East was begun. A small amount of fossil layer was excavated before a section of the overburden above and to the north of the fossil layer was removed with Atlas Copco jackhammers. An area of approximately 2.5 metres by 1.5 metres of overburden was removed to a depth of 60 centimetres on the northern face. This was done to facilitate the removal of the fossil layer below.

The excavation of the fossil layer in this defined area took four weeks. Doris Seegets-Villiers mapped the face of the fossil layer a number of times over this period, and recommended that the fossil layer which contained the two mammal jaws recovered the previous December, continued west of the excavation. Her suggestion was that we should consider moving in that direction instead of east back towards last year's excavations.

At the end of the fourth week of the field season we had removed the entire targeted fossil layer in the original excavation, cataloguing over 600 fossil bones and teeth, including two more mammal jaws.

John Wilkins found the first mammal jaw during the second week of the dig, but unfortunately, it was not complete, and the two preserved molars were badly damaged.

On the last day of the fourth week, Saturday 17th February, we held the "Friends of Dinosaur Dreaming" day where close to 100 supporters joined us for a special tour of the site. It was during this activity that Gerry Kool discovered the second mammal jaw, and it is the tiniest jaw found so far.

As we finished removing the last of the fossil layer from the excavation, it was decided that we would sample part of the lowest layer directly above the mudstone. There was only a small part of the lowest fossil layer exposed on the edge of the channel. A number of small bones had been exposed in this layer in the past, but we had never sampled the layer, preferring to concentrate on the upper fossil layers below the overlying sandstone.

Fish and turtle bone fragments were quickly discovered, which was to be expected, as they constitute the highest percentage of fossil bones found at this site. However, a small tooth was also discovered, which was later identified as a possible pterosaur tooth. Further excavation of this part of the fossil layer revealed a number of other bones, including a nice dinosaur toe bone and the shaft of a small dinosaur limb. This lowest layer does not appear to be as fossiliferous as the upper layers, but warrants further investigation.

On Doris Seegets-Villiers advice it was decided that we spend the last two weeks of the field season expanding the excavation by one metre to the west. This required a small amount of overburden to be removed, which was accomplished in a few hours. As with the previous four weeks, most of the fossil bones recovered were less than five centimetres in length, reflecting the reduced carrying capacity of the original stream at this point in the deposit. An exception to this was the discovery of an almost complete hypsilophodontid femur by Dale Sanderson, which at 15 centimetres in length, was the largest bone found during the field season.

A number of shed theropod dinosaur teeth are found each field season and this year was no exception. Since excavations began at the Dinosaur Dreaming site in 1992 more than 50 small theropod dinosaur teeth have been recovered. With one exception, all the teeth were shed from the mouths of these meat-eating dinosaurs while they were still alive. The evidence for this is shown in the absence of roots on the teeth.

All dinosaurs replaced their teeth throughout their lives. When a tooth was worn or broken the root was resorbed into the jaw, leaving just the crown of the tooth held in place by the gums. The tooth would often become embedded in the flesh or bone of the animal the theropod dinosaur next bit into, or sometimes it was swallowed. Eventually, these isolated teeth ended up in the fossil deposit, only to be discovered many millions of years later.

The discovery of these beautiful, shiny serrated teeth are always cause for excitement, as they represent animals that may have been feeding in this area so long ago. Towards the end of this field season Astrid Werner, an experienced volunteer who has joined us for the last five field seasons, found a small theropod tooth. Her tooth was the exception to the rule and gave us all hope for the future, for this tooth had a root.

This was not a shed tooth, but a tooth which would have still been in place in the jaw of a small theropod dinosaur when it died. This discovery, along with several small theropod vertebrae and some isolated skull fragments also recovered this field season, suggest that maybe a small theropod dinosaur died in the vicinity and its scattered bones and teeth found their way into this part of the fossil channel. There is no guarantee that more of this individual will be found during future excavations, but it does give us reason to hope.

Before the field season commenced Barry Clarke, a local geologist who was keen to become involved in the project, contacted us. Barry's knowledge of the Strzelecki area was a great asset, which we felt was important to use. Barry joined us at the site on a number of occasions and when we expressed interest in prospecting some of the inland outcrops, he generously arranged for us to gain access to some private properties that had exposures that could be of interest.

Although the excavation of the fossil site near Inverloch is our primary aim, it is also important to spend some time prospecting for new sites. The idea to prospect inland of Inverloch was suggested when it was discovered that the local shire was planning to straighten parts of the South Gippsland Highway, which winds its way through the Strzelecki hills to the north of Inverloch. The important fossil site at Koonwarra was discovered during the original building of the highway in the 1960s and so it was hoped that by straightening some of the bends in the highway, more fossiliferous sites might become exposed.

As it turned out the Shire had only just begun work on the Highway and not in the area we wanted to prospect, so Barry suggested we travel to the small town of Jumbunna not far from Inverloch and check a property that he had permission for us to enter. Here, he believed, we would find outcrops of the upthrown side of the Kongwak fault, exposing Early Cretaceous sediments.

We travelled in convoy to the property where we checked along the banks of the creek and climbed to the top of a nearby hill looking for exposed outcrops. Small outcrops of mudstone and interbedded sandstone were found along with a few plant fossils, but no evidence of fossil vertebrates.

We then prospected some road outcrops along the Jumbunna-Outtrim road. We surveyed the road first, noting there were a number of outcrops to be explored. Then we turned around and drove back along the road, one car stopping at each outcrop and then leap-frogging the other cars to the next free outcrop. This way the six vehicles covered all the outcrops quickly. Most were comprised of massive sandstone, with small amounts of interbedded mudstone.

A fairly extensive exposure of sandstone/mudstone and coal was discovered that was part of the old rail cutting. An extensive investigation of the cutting took place once permission from the owners was obtained, but no evidence of vertebrate fossils was discovered.

Although no evidence of fossil vertebrates was found during the prospecting trips, both Barry Clarke and Mike Cleeland are keeping in touch with the Shire's progress of straightening parts of the South Gippsland Highway as there is real potential for new fossils sites to be exposed.

As well as the inland prospecting we also spent one day working the "Ferguson site" at Eagles Nest. This site is named after William Ferguson, a geologist who found the first dinosaur bone in Australia in 1903, and although the map he drew does not exactly pinpoint the location, we are fairly sure that the fossil site discovered by Mike Cleeland in 1995, is the same locality. The site is also situated in the intertidal zone and often covered with sand. Although not as fossiliferous as the main Dinosaur Dreaming site at Flat Rocks, it has yielded some interesting specimens in the past, including a partial pterosaur or bird humerus, which Pat Vickers-Rich is currently studying. This field season eleven specimens were collected, including a small plesiosaur tooth, approximately 1.5 centimetres long. The rest of the specimens were mainly fish and turtle, but we will return to the site again next year.

Visitors

One of the most enjoyable aspects of the field trip is interest shown by overseas researchers. This field season researchers visited us from Patagonia, England, Alaska and Japan.

Raúl Vacca from Patagonia is a very experienced field worker, who spent three weeks with us and gave us the benefit of his extensive knowledge in excavation and preparation. Our site is very different to the arid desert conditions of Patagonia where Raúl has excavated large complete dinosaurs. Recognising tiny bone fragments was quite an experience for him.

Dr.Robert King works for the Bureau of Land Management in Alaska and had heard about our dig from Katch Bacheller, our "Evil Overseer" and fellow Alaskan. As he was in Australia visiting relatives it was a perfect opportunity for him to see the site first-hand. We were very fortunate that Bob had brought with him slides of another Polar dinosaur site on the banks of the Colville River in Alaska and we enjoyed a very pleasant evening viewing excavators on the other side of the world working in even more difficult conditions than ours.

For the last week of the dig three researchers from Japan and one from England joined us. Dr. Makoto Manabe, from the National Science Museum in Tokyo, works on hypsilophodontid dinosaurs and was particularly interested in our excavation techniques. His colleagues included Dr. Yoshitaka Yabumoto, who is a palaeoichthyologist and was interested in the fossil fish we were collecting. Dr. Sue Evans from Imperial College, London, was interested in fossil frogs and lizards, but unfortunately we were unable to help her in either of these groups, as they both appear to be absent from our fossil fauna.

The fourth member of the group was Ryoko Matsumoto, a young preparator who wanted to learn more about our method of preparation. Ryoko stayed on in Melbourne after Makoto, Yoshi and Sue returned to Japan, and spent three weeks learning how to use our preparation tools and consolidants. In that time she prepared a number of small fossil bones that she had brought with her from Japan using her new knowledge.

Follow up

Preparation of the four new mammal jaws was completed after the field season and has produced some interesting results, which Tom Rich outlines in his report. Two papers have recently been published; one describing Bishops whitmorei, the newest genus and species belonging to the Ausktribosphenidae and a brief report on Teinolophos trusleri and its monotreme nature. Tom is currently working on the tiniest mammal jaw, found this field season, which may also be a new genus and species.

One of our field crew, Natalie Schroeder, was lucky enough to procure a preparation job at the Royal Tyrrell Museum of Paleontology in Alberta, Canada. She left Australia in May and carried with her a precious cargo of most of the theropod teeth from Inverloch, including the tooth with a root. When she arrived at the Museum she handed the teeth over to Dr. Phil Currie, who specialises in theropod dinosaurs. He has been studying the teeth and we hope to have his thoughts on them in the near future.

Late in 2000, we successfully applied for a Community Grant through Parks Victoria on behalf of the "Friends of Dinosaur Dreaming". This grant will pay for the creation and construction of a series of interpretive panels to be erected at the Dinosaur Dreaming site near Inverloch. We have provided text and illustrations for the panels and graphic artist Graham Kenneday will produce the enamel panels. It is hoped that the panels will be finished in time for the Dinosaur Dreaming 2002 field season.