Monday, May 31, 2010

Where Have All the Fossils Gone?

Today (Monday, May 31) was the first where the sun made more than a furtive appearance, with blue skies and brightness illuminating the outcrops. Our goal was to scout a locality called Harmers Haven, which Tom had not seen before this trip. I had visited it three years ago, but remembered little from it, and was reminded why today.

Harmers Haven at low tide.

We went at low tide in the morning, which exposed the rocks along the mostly flat marine platform for kilometers to the east. It was a daunting sight, but we walked to the easternmost end of outcrop and worked our way back, looking for trace fossils and bones. The amount of rock to examine was enormous, and the tide was rising, so not much detailed study could be done of the geology. Within just 2½ hours of arriving, we were driven off the outcrops by the encroaching sea, and had found nothing worth noting. No definite trace fossils or bones were seen, although the rocks did contain a huge amount of carbonized fossil wood, including large chunks of tree trunks.

Fossil plant debris, all shredded and carbonized.

Parts of a fossil tree trunk, with my size 8½ (men's) boot for scale.

Why? How could two paleontologists, one trained in discerning trace fossils and the other in identifying fossil bones, spend hours on a great expanses of Cretaceous-age rocks, yet find nothing more than fossil plant debris? (Not that there’s anything wrong with fossil plants – as my paleobotanist friends will attest.)

The answer is probably related to the science of
taphonomy, which is the study of fossil preservation. Sometimes I summarize taphonomy as “everything that happened to an organism after it dies,” but it also can be applied to trace fossils, such as dinosaur tracks or crayfish burrows, which require special conditions to get preserved in the fossil record.

Body fossils and trace fossils are already exceptions compared to all of the life forms and their traces that have lived in the past 4 billion years that did not get preserved. But fossilization could have been made even more rare under given circumstances in the geologic past, even if a place was teeming with life.

First of all, this part of Victoria, Australia was near the South Pole during the Cretaceous Period. The rocks we looked at today, which are 115-120 million years old, were formed near about 75° S latitude. Australia was even connected to Antarctica at the time.

Position of Australia relative to the South Pole during the Cretaceous and today. From a sign at the Flat Rocks (Dinosaur Dreaming) site.

So you would think not much was living here then, but you would be wrong (sorry about that). Global temperature was quite a bit warmer than today, and forests actually extended to the poles. Which is why this area has lots of fossil plant material, as there were many trees living upstream of where these.

And that is a key statement: living upstream of here. All of the trees and other fossil woody materials were transported, perhaps many kilometers from where they lived originally. None of them lived here, as not a single tree stump has been found in place, and neither have any root trace fossils been seen.

The same is true for nearly every fish, amphibian, reptile, dinosaur, and mammal bone found in the Cretaceous rocks here in Victoria. And transport means incompleteness, as traveling downstream can be a little tough on body parts. So nearly all that people find are bits and pieces of these animals. They were very likely not living in the same environments where their remains were buried.

For example, the very first dinosaur fossil found in Australia, a single dinosaur claw, discovered by geologist William Ferguson in 1903.

The “Cape Paterson” claw, found by William Ferguson on the Victoria coast. Source of photo:

Here I am at the original site where this dinosaur claw was found.

Oops, sorry - wrong photo! (And I have no idea how it got on my computer.) Here’s me at Eagle’s Nest, at the approximate site of Ferguson’s discovery:

More than 70 years passed by before anyone found any other dinosaur fossils in this area. And despite their re-discovery since the late 1970s and intensive recovery efforts near where we were today and west of Melbourne at Dinosaur Cove, all of the dinosaur bones that have been found from Victoria could easily fit in a single room. Even more depressing, all of the mammal bones could fit in a matchbox. And this is related to how these bones were not buried in the place their former owners once lived. Only a very few lucky parts made it into the fossil record.

Most trace fossils, on the other hand, have a great advantage in that most are not transported. When you see a dinosaur track, it is exactly where that dinosaur stepped on the ground, and when you see a fossil crayfish or insect burrow, it is likewise right where those crayfish or insects were living. The same goes for root trace fossils. If any of these were preserved here, I could say that plants were definitely living in the same places we are walking across.

But now think about these polar environments and how fossil preservation would be affected. This area had a series of rift valleys, which meant high, hilly areas with lots of rocks and steep slopes, and frozen landscapes in the winter. What happened in the spring, when everything thawed out?

You guessed it: torrential run-off of melted ice and snow. And that’s what these rocks show, which are very high rates of flow. Entire trees and lots of other plant parts were transported downstream, along with much more rare bones. I imagine raging rivers here 115-120 million years ago, choked with mud, sand, pebbles, cobbles, and boulders, that scoured deeply into the landscape each spring.

Boulder embedded in sandstone at The Oaks, representing the strength of the Cretaceous river that carried it during a polar spring. Tom Rich for scale.

Later in the polar summers, as these flows subsided, their sediments were dumped into the bottoms of river channels and onto floodplains. Only then could dinosaurs or other animals walk in through here, leaving tracks or donating their bodies to the fossil record for future research. Then came winter, with little to no flow of water and sedimentation, followed in the spring by great eroding floods, erasing body and trace fossils that might have been preserved. And for many of the tracemaking animals, they would not even be living here in the first place to make their traces. So there would be nothing to preserve, anyway.

So for upcoming days of
The Great Cretaceous Walk, we will pray to the Goddess of Taphonomy to grant our wishes for more bountiful examples of body and trace fossils. With this hope in mind, we will begin looking at the westernmost outcrops of the Strzelecki Group.

Sunday, May 30, 2010

Flat Out on Flat Rocks

Thursday, May 27 was the first official day of the Great Cretaceous Walk, with some great walking on and by some great Cretaceous rocks from then through today, Sunday, May 30. Just before we started walking, though, Tom (Rich) and I drove from Melbourne to Inverloch, Victoria, which took about two hours. Once there, we checked into the Inverloch Motel, which is such a quaint and old-fashioned motel that it does not have Internet access: hence the lack of entries for the past four days. (Many thanks to Lesley and Gerry Kool for offering their wireless to post this!)

Flat Rocks (Tom Rich sitting to the left).

After that and lunch, the first place we visited, and where the walking began, was Flat Rocks. Our start here was appropriate for several reasons. One is that this is a of classic fossil locality in Australia, the site of the annual Dinosaur Dreaming dig site. Each January-February, Monash University and the Museum of Victoria have organized a 4-6 week volunteer-driven excavation of a rock layer that contains the remains of dinosaurs, mammals, and other Cretaceous animals.

Volunteers at Dinosaur Dreaming dig site in February 2006.

This dig requires major effort, in that the rock is very hard – sometimes requiring jackhammers and other power tools, but normally using hand tools – and the site is underwater twice daily from the tides. During those times of high tides, many kilograms of rock are transported to an offsite location, where volunteers break up larger chunks into much smaller ones (“sugarcube” sized), looking for small bones and teeth. This is not the type of dinosaur dig where complete and fully articulated skeletons emerge; rather, bits and pieces are the norm. Despite the name “Dinosaur Dreaming,” by far the most valuable fossils found here are tiny mammal jaws, some of which provide insights on the early evolution of mammals in Australia.

As my faithful readers may already know, Flat Rocks is also the place where four years ago I found fossil crayfish burrows, the first known Mesozoic crayfish burrows in Australia, as well as two partial dinosaur tracks. A dig-site volunteer then found a third dinosaur track the following year. This place is also near the easternmost extent of Cretaceous rocks along the Victoria coast, so it was a good place to start as we move from east to west.

Flat Rocks and an area just east of it, called The Caves, took up Thursday afternoon (May 27). All day Friday (May 28) was spent walking around the area of Eagle’s Nest and Shack Bay, just west of Flat Rocks. On Saturday (May 29), we went a little further west of Eagle’s Nest to Shack Bay (again), Twin Reefs, and the eastern half of The Oaks. The timing of the tides conspired with strong waves on Sunday (May 30) to limit our field work to the morning. Regardless, much was accomplished, as we traversed the western part of The Oaks, then went further west to outcrops along Undertow Bay and Cape Paterson.

Eagle’s Nest.

Eagle’s Nest is named about the prominent and photogenic erosional structure there, and is an easily visible landmark in the eastern part of the Cretaceous coastal outcrops.

Shack Bay.

I’m not sure what Shack Bay is named after, as I saw no shack, although it definitely is a bay.

Twin Reefs.

I’m assuming Twin Reefs has two reefs offshore, unless this name is used as some sort of Australian metaphor to which I am not privy.

The Oaks, eastern portion.

The Oaks, western portion (with a beach in between the two outcrops).

No oaks were seen at either half of this locality, although a few fossil trees from the Cretaceous were preserved in the rocks there.

Undertow Bay.

We are guessing that the name of Undertow Bay tells visitors that it is not the best place to go for a swim. Walking along this outcrop had an adventurous feel to it, no doubt encouraged by the waves smashing against the rocks all around us.

Cape Paterson.

Cape Paterson was a bit more genteel than Undertow Bay, but still wild and wooly in spots. Fortunately, it had relatively easy access and wide platforms just below the cliffs. Still, the oncoming high tide led to a hasty retreat, so field work on Sunday was cut short.

So why am I doing this again? The main goal of The Great Cretaceous Walk is to document more trace fossils and note their locations in the Cretaceous rocks of the Victoria coastline. This mostly involves a combination of old-fashioned walking and looking for the right search images, which is how paleontology has been done for the past 200 years.

But in this case, it is being done with a modern technological twist. I have been using a GPS (global-positioning system) unit to record the locations of each trace fossil I encounter. This is done by leaving the GPS device on during each excursion, then using it to mark the place of each trace fossil as a “waypoint.” In a notebook, using a pencil (yes, that’s old-fashioned, too), I’ve written the waypoint numbers (001, 002, etc.), noted what trace fossil was there, and photographed them with a digital camera (that’s another modern technological twist). Later, I will correlate the recorded times on the GPS unit with those of the digital photographs, and the waypoints will be put into a GIS (geographic information system) file so that these can be placed on a digital map. At least, that’s my hope!

How is it going? Pretty good, although most of the trace fossils consist of probable crayfish burrows of various shapes, sizes, and preservational modes. Most are filled with sandstones that are colored differently from the surrounding sedimentary rock, which sometimes helps me to spot these trace fossils from more than 10 meters (33 feet) away.

But for me to record these as trace fossils, they must fulfill some strict descriptive criteria. For example, here is an excellent example of one of the probable crayfish burrows, showing a beautifully expressed horizontal network, branching tunnels, enlargements between branches, connections to vertical shafts and consistently sized tunnels.

Fossil crayfish burrow from the Strzelecki Group, about 115-120 million years old: view is looking down onto the horizontal expression of the burrow system. Scale is about 15 cm (6 inches).

In fact, paleontologists have a name for a trace fossil with this form: Thalassinoides. We give formal names to trace fossils for better communication with one another, although the names normally have nothing to do with the animal that made the trace fossil.

So far, I have recorded more than 25 locations with Thalassinoides, which is not bad for about three days of field work. However, sadly – just short of tragically – long stretches of these coastal exposures have no visible trace fossils at all. For one, dinosaur tracks, which are common in some Jurassic and Cretaceous rocks of the American West, are annoyingly absent from nearly everywhere we’ve looked so far. Also, in three days of walking, Tom Rich and I have not seen a single dinosaur bone – or any other fossil bone for that matter.

Why are both dinosaur tracks and bones so rare here? I (and others) suspect that this circumstance is related to the environments that produced these rocks 115-120 million years ago. And that is the subject of the next entry…

Wednesday, May 26, 2010

First Field Day: Inverloch, Victoria

Today we (Tom Rich and I) leave Melbourne for Inverloch, Victoria to start walking along the Cretaceous coast. Once there, we will go from the east to the west until the sun goes down (which will be around 5:15 p.m. here). Hopefully the weather and the rocks cooperate with us today, and the trace fossils will whisper sweet nothings to us, beguiling us and revealing their secrets. Look for a report later!

Tuesday, May 25, 2010

Luck, Preparation, and Opportunity: Part II

"You won't find anything."

This assurance came from Tom Rich as he drove, and me as his sole passenger on a quick trip to the Victoria coast. At his invitation, we were traveling together to Flat Rocks, the Dinosaur Dreaming dig site near Inverloch, Victoria. It was late February 2006 and the last weekend of the dig season there. It was a privilege for me to witness the closing of yet another successful field season and meet some of the people associated with Dinosaur Dreaming. But at the same time I was entering an intellectual unknown.

Dinosaur Dreaming, February 2006

I had been in Australia for less than three weeks, on a sabbatical from Emory University for the first time in 16 years. The primary reason for my being there was to work with Patricia (Pat) Vickers-Rich on a geoscience-education project, but I was open to any other opportunities that might arise. So when Tom asked me if I would like to come with him to the coast, I emphatically said “yes,” albeit with a blend of awe, excitement, and trepidation. The last of these feelings stemmed from my being in a new place, with new people, and new rocks (an example of how “old” becomes “new” in geology). The still-healing fractured tibia in my right leg, the result of a biking accident only a month before, also reminded me to take it slowly, and I had brought a walking stick with me to help with traversing the flat platform of rock. (Yes, the person who first named “Flat Rocks” must have had a lack of imagination that day.)

Flat Rocks, near Inverloch, Victoria.

Tom’s pessimistic statement came in response to my observing that in 14 years of work at the Flat Rocks site, a source of some major paleontological discoveries, no trace fossils had been detected, yet I expressed hope that I would find some there. His pessimism, though, was based on what was known then. The only trace fossil described from Early Cretaceous rocks both east and west of Melbourne was a single, small dinosaur track from the Otway Group, in rocks dated at about 106 million years ago and from Knowledge Creek. Pat and Tom found this track in 1980, during their only time to Knowledge Creek, a place they swore they would never visit again because of its remoteness and difficult access.

No fossil burrows, not even those of invertebrate animals – such as insects or crayfish – had been reported from kilometers of expansive Cretaceous outcrops. Invertebrate trace fossils, especially burrows, are normally the most common trace fossils in any given sedimentary rock sequence, and I thought it was unusual that none had been described after more than 100 years of geological research in this area.

Fortunately for both of us, Tom was wrong. I found two isolated large theropod dinosaur tracks the first day, the first such tracks discovered from this site, then found fossil crayfish burrows the day after that.

Fossil crayfish burrows at Flat Rocks, Strzelecki Group, 115-120 million years old. Burrows were filled with a differently colored sand while the surrounding sediment was still soft, and both sediments later cemented to form sandstones. Photo scale = 10 cm (4 inches).

I promptly celebrated this discovery by sitting on them.

Me sitting on Cretaceous fossil crayfish burrows: photo by Gerry Kool.

Although the dinosaur tracks were nice to find, I actually was more excited about the second day’s discoveries, for reasons explained later. The fossil crayfish burrows led to a paper that took nearly two years to write and publish, but one that was well worth it for its contributing to the solution of a 130-year-old evolutionary puzzle first posed by famed evolutionary scientist Thomas Huxley.

This new knowledge thus alerted future dig crews to start looking for more trace fossils, and especially dinosaur tracks. Sure enough, the next year, in February 2007, an undergraduate student, Tyler Lamb, found a third large theropod track, only 5 meters (16 feet) from the dig site.

Large theropod dinosaur track, preserved as a sandstone fill of an originally concave feature, and weathered out in bold relief. Yup, same photo scale as in the previous picture.

The humbling realization for everyone after this find was that hundreds of volunteers and professional paleontologists had walked across this track for nearly 15 years, unknowingly putting their feet on the same spot where a dinosaur had stepped 120 million years earlier. Hence my own luck, preparation, and opportunities enabled others to make their own discoveries, using the same winning combination of fortune, knowing what to look for, and circumstance.

Tomorrow, Tom and I leave together for Inverloch and will walk over the same rocks, more than four years ago, with both of us expecting to be surprised by what we find. The next post should be about our progress, but also be looking for one that explains why the fossil crayfish burrows were more important to science than the dinosaur tracks, and how these were connected to Mr. Huxley.

Monday, May 24, 2010

From the Southeast (of the U.S.) to the Southeast (of Australia)

Traveling to Melbourne, Australia from Atlanta, Georgia is both easy and not easy. I say this now after having just completed my seventh trip here, so the voice of experience may sound a bit weary, yet is still filled with excitement about having made my way here again.

Atlanta is a major hub for commercial air traffic, and in fact Hartsfield-Jackson International Airport is the busiest in the world when measured by number of passengers that pass through it. (The old joke in Atlanta is that after you die, before you go to heaven or hell, you change planes in Atlanta.) So it was easy enough to take a direct flight to the Los Angeles International Airport (LAX) from Atlanta and arrive there in five hours. The “not easy” part of every trip to Australia starts as soon as I step off the plane and enter LAX.

I strongly dislike this airport. It is a very unfriendly place, with few personnel available to direct or otherwise assist people, no signs guiding people to the international terminal, and no people movers (such as light rail) to ease the transition from domestic to international travel. No one seems happy here, and few smiles are seen, nor are many laughs heard and exchanged.

This time was no exception, and the tardy domestic baggage-claim, an uncertainty of where to check in for the connecting flight to Australia, and the Rube-Goldberg maze called “security” at LAX, all led to an unnecessarily anxious and stressful time between flights. What seemed like a last-minute check-in at the Qantas gate did not result in my boarding an aircraft, either. Instead, similarly nervous passengers and I were directed to a bus that stood motionless on the tarmac well past the time the plane was supposed to leave. The silence on the bus spoke of everyone’s wondering if we had already missed our flight, and weighing our options if we had.

Once the bus was full, a driver appeared and took us for a long ride through lonely expanses of airport concrete, a stark emptiness punctuated by runway lights, hangars, large passenger planes, and occasional vehicles. After nearly 15 minutes of riding, we arrived at an isolated building next to our plane, the latter recognizable through the Qantas logo, a crimson-kangaroo silhouette. After walking up several flights of stairs in the building, we finally boarded our plane, and sat in our seats for another 45 minutes or so before the long taxi and take-off, more than an hour past our scheduled departure. It was 12:40 a.m. Los Angeles time, and 3:40 a.m. back in Atlanta.

About 15 hours later, we landed in Brisbane, Australia. Attentive readers will note that Brisbane is not the same place as Melbourne, and is actually halfway up the east coast of Australia. Melbourne is located in the southeastern part of Australia, just north of Tasmania.

You are here and not here: locality map for Brisbane and Melbourne in Australia.

Strong winds from the west had impeded our flight enough that it needed to refuel before continuing to Melbourne, and Brisbane was chosen as the place to do that. We stayed on the plane while it refueled for nearly an hour, and took off again for an additional two-hour flight to Melbourne. All told, about 18 hours were spent on the same plane.

Once in Melbourne, though, it became easy again. Immigration, baggage claim, and customs took all of 20 minutes. In the Melbourne International Airport, you feel welcomed to Australia. A bus ticket took minutes to purchase; another minute was needed to walk outside to the bus that drove directly to downtown Melbourne; another minute to catch a quick taxi ride to the Melbourne Museum.

Exhibition Hall of the Museum of Victoria.

So less than an hour after landing on that cloudy Monday morning, I was shaking Tom Rich’s hand and chatting amiably with him and other friends at the museum about all things paleontological. Later that same afternoon, I looked in museum collections at fossil insects from the Koonwarra Formation, an Early Cretaceous sedimentary deposit east of Melbourne. LAX was now an errant bad dream, fading into insignificance as I stared at the remains of mayfly nymphs preserved on a lake bottom from more than 115 million years ago. Perspective helps.

This is the surreal part of such travel, informed and motivated by paleontology. After all that transpires, you are back in a familiar world, one where hours and minutes are meaningless, and the fossils and rocks give you reason to understand that it was all worth the hassle. Because ultimately it is much easier for you to go to the rocks and fossils than for the rocks and fossils to come to you, and your time spent to greet them diminishes when viewed in the light of what brought you there.

That evening, walking with Tom through Carlton Gardens outside of the museum, I spotted a mother brushtail possum ambling along, carrying an ample-sized youngster on her back. They were startled when I stopped to look at them, and the young possum reacted by jumping off momma-possum’s back. They each ran a short ways before turning to stare back at me, this odd person who is curious about them. Like squirrels in the U.S., they are more used to people ignoring them, urban wildlife that becomes as much a part of the local background as a traffic light. I smile and delight in having this brief connection with these commonplace animals that so much define this place, despite the bemused reactions of Australians to my interest.

That was yesterday here, Monday, May 24. Today holds more museum time, more settling into this place and time, and preparations for field work starting on Thursday, the unofficial start of The Great Cretaceous Walk. Look for an entry that continues a story of a previous time here, titled Luck, Preparation, and Opportunity: Part II.

Saturday, May 22, 2010

Today is a travel day from Atlanta, Georgia (USA) to Melbourne, Victoria (Australia), a 24-hour (plus) journey, if all goes as planned. Once I'm there, be looking for Part II of Luck, Preparation, and Opportunity.

Friday, May 21, 2010

Luck, Preparation, and Opportunity: Part I

In the previous entry, I promised to ask and answer the question: how did The Great Cretaceous Walk come about? It’s a long story (by human standards) that could very conveniently start with me in 2005. But the truth is, it began a bit longer ago, in 1903. An Australian geologist, William Ferguson, was mapping rocks along the coast of Victoria, near the town of Inverloch, when he found a single claw, nicknamed the “Cape Paterson claw” (after nearby Cape Paterson). It turned out to be the first known body fossil of a dinosaur from Australia, and it came out of rocks from the Early Cretaceous, from about 115-120 million years ago. Its location was noted along with other bones, just southwest of a distinctive coastal feature called Eagle’s Nest. Here’s an excerpt of Ferguson’s map and his notations:

For now, also notice that Ferguson recorded “large ferruginous concretions in sandstone” just south of where he mentioned the presence of bones. These features would have significance much later, especially related to my study of trace fossils in this area.

Surprisingly, 75 years went by before more people looked for fossil evidence of dinosaurs in this area, when geologist Rob Glennie and two students, John Long and Tim Flannery, revisited the area in 1978. They found more skeletal material of dinosaurs and a previously unknown amphibian, which encouraged Tom Rich of the Museum of Victoria to examine geological maps of the areas east and west of Melbourne for more Early Cretaceous-age rocks. This led to prospecting of the Otway Group rocks to the west of Melbourne, and much walking along the coast: the original “Great Cretaceous Walk” (although they didn’t call it that).

All of the walking paid off, when in 1980 Tim Flannery, Mike Archer, and Tom Rich found a good number of dinosaur bones in rocks exposed along a cove. Well, Tom Rich named the cove that day – oh so nonchalantly – Dinosaur Cove.

This name not only stuck, it became world-famous as a final resting place for the remains of polar dinosaurs. From 1984 through 1994, tons of rocks were smashed, jackhammered, exploded, or otherwise abused to yield their 106-million-year-old paleontological secrets, and the results were spectacular, telling a detailed story of life on land near the South Pole at that time in earth history. This unique scientific endeavor and the human stories behind it are summarized in Tom and Pat Vickers-Rich’s book, Dinosaurs of Darkness (2000, Indiana University Press).

Once Dinosaur Cove was exhausted of its resources (and its volunteers were exhausted as well), a new dig site began in 1994, Dinosaur Dreaming. This dig site is in the kinder, gentler location of Flat Rocks, only a few kilometers from where William Ferguson originally found the first dinosaur fossil in Australia.

Now, keep in mind that these rocks are about 10 million years older than those of Dinosaur Cove, so the two places provide a “connect the dots” sort of view of how life changed in this area during the Early Cretaceous. Most significantly, this has been the site for many mammal fossils, some of the oldest in Australia. Hence a few people suggested that it be renamed “Mammal Dreaming.” But for some reason this new nickname hasn’t caught on, yet another example of how mammals haven’t gained much respect when used in conjunction with the word “dinosaurs.” And invertebrates? Forget it!

Well, you won’t forget for long, though, because I’ll soon point out how invertebrate animals fit into the larger picture of dinosaurs, mammals, and other denizens of these Early Cretaceous polar landscapes. My next entry will tell of when I visited Flat Rocks, in February 2006, and I first saw these Cretaceous rocks of Australia that never fail to surprise us with its paleontological wonders: Luck, Preparation, and Opportunity: Part II. See you then!

Thursday, May 20, 2010

Traveling Across a Continent, Ocean, and Time

Only two days remain before traveling to Melbourne, Australia, a 24-hour journey that starts in Atlanta, Georgia and connects (mercifully briefly) through Los Angeles, California before flying across The Big Pond to Oz. In Melbourne, I will meet with friends who will help me to begin what I’ve dubbed The Great Cretaceous Walk.

And just what is meant by “The Great Cretaceous Walk”? Well, the “great” part of this label is not applied out of grandiose expectations for what might happen, but partially refers to “The Great Ocean Road,” a drive along the Victoria coast west of Melbourne that is often rated one of the most spectacular in the world. One of the reasons why this drive is regarded with such awe is because of the extensive seacliffs and marine platforms that line the shore where the Bass Strait meets the mainland of Australia. Similarly, a 104-km (65-mi) long trail that winds from Apollo Bay to The Twelve Apostles, an iconic string of seastacks, was given the name “The Great Ocean Walk.”

OK, that’s the “Great” part. What about the “Cretaceous” part? Most of the rocks composing this vista west of Melbourne fall within the Early Cretaceous Period, a geological time unit that spans from 145 to 100 million years ago. Rivers and lakes formed these rocks about 110 million years ago, with their sediments dumped during many summers of a polar climate (more about that “polar climate” in future entries). Geologists and paleontologists refer collectively to these rocks as the Otway Group, named after Cape Otway in that region. In the Otway Group are the remains of dinosaurs, mammals, turtles, fish, clams, insects, crayfish, and plants, painting a picture of what lived in these rivers and lakes then. Most importantly, from my skewed perspective, these rocks also hold the echoes of past behavior, preserved as burrows, tracks, and other vestiges called trace fossils. These are what will be sought on this walk, and these (I am confident) are what will be found.

But only half of the story told by the Great Cretaceous Walk is in these rocks west of Melbourne. Melbourne is nearly equidistant between two great Cretaceous coastal outcrops: those of the Otway Group, and those of the Strzelecki Group to the east. These rocks are slightly older, at around 115-120 million years old, with the “slightly” modifier as a geological conceit along the lines of “what’s a few million years between friends?” Still, these rocks are in the Early Cretaceous Period, too, and these also contain bits and pieces of some of the earliest known mammals of Australia, as well as dinosaurs and many other animals. In fact, one of the best sites in the world for polar dinosaurs is at Flat Rocks, where the Dinosaur Dreaming dig takes place every year, starting in 1994.

The “Walk” part is fairly straightforward: I plan to walk along this coast. And wherever Cretaceous rocks and their trace fossils might be, I plan to document these and their locations. The current plan is to start in the east and walk to the west, but like all field-based work, I expect that plan will change somewhere along the way. Regardless, I will be walking a lot. (And yes, you might apply the expression “walkabout” to this endeavor.)

But for now, preparations for travel, the travel itself, and recovery from that travel will need to happen before that first step is taken on the Cretaceous rocks of Victoria. This is where my Australian friends Tom Rich, Pat Vickers-Rich, Lesley and Gerry Kool, Dave Pickering, Mike and Naomi Hall, Mike Cleeland, and many others will prove invaluable as my “support group” in this project, especially once I arrive in Oz. Wish us luck!

The next entry will ask (and answer) the question: how did the Great Cretaceous Walk come about? See you then!