Rocks with a Role

Dave Young, reporter for The Saint John Times Globe (with some editing by Randy Miller, Curator of Geology and Palaeontology, New Brunswick Museum).

For more than a century, New Brunswick has played a key part in giving scientists a sense of how things came to be as they are today.

If you strolled along the base of the cliff it would be virtually unnoticeable, a shallow hollow in the miles of rock along the Bay of Chaleur.

If, for some reason, you stood in that two-metre depression for a few minutes, you might get a sense of why it is called The Fly Pit. But unless you stood there with someone like Pat Gensel, braving the black flies and mosquitoes and hammering away at the rock, you would never know that this place is special.

Much of what the world knows about early plants, about how and when they began to evolve from simple green sticks into complex branches with leaves and seeds, comes from these rocks - places like The Fly Pit, or ones with more functional names like Fir st Creek or Second Creek.

In the world of fossils and plant evolution, Dalhousie Junction is on the map.

In fact, for more than a century, New Brunswick has played a key role in giving people a sense of how things came to be as they are.

People like Pat Gensel have explored these rocks for 20 years now. And there were others before her. The rocks in this area - on both sides of the Bay of Chaleur - have been examined for more than a century by scientists like McGill University paleon tologist John William Dawson and in the south by Saint Johners like George Matthew and his son William.

Journals dedicated to fossils and evolution, and museum collections around the world, are salted with New Brunswick references: Campbellton, Hanford Brook, Duck Cove, Clifton, Fern Ledges, Albert Formation, Avalon and the Forest Hills Formation.

Admittedly, in the more fickle world of popular fossils - that is, the ones they make movies about - New Brunswick doesn't even exist. After all, there are no dinosaurs in New Brunswick. Very few rocks in this province are young enough to hold fossil ized dinosaurs.

But if you want to know about life before the dinosaurs, about early fish, plants, prehistoric insects or some of the world's oldest fossils, New Brunswick is the place to be.

Which is why you find Bill Shear pounding away at the rocks here again and again and again.

Figure 1.

It is an afternoon in June and, even from the back, you can tell his mood has changed since the morning. His shoulders seem tight as he hunches over a slab of grey rock, chipping, examining, discarding and chipping again in a peculiar rhythm. But he is quieter than before. In the morning, he was picking away at rock faces at Dalhousie Junction with some excitement. Bill Shear, a paleontologist from Hampden-Sydney College in Virginia, expounded on the theories of evolution, about how fossils are form ed, about the state of science in general. Now he is silent except for sighs.

This is not moodiness, but determination and passion - the sort that drives people to spend their adult lives searching the rocks for clues.

Shear's expertise is in arthropods, the hard-shelled, backboneless animals that still dominate the world: insects, millipedes, spiders, scorpions, crustaceans.

A few hours earlier someone found a fossil of one. Steve McCutcheon, a provincial geologist who was one of a number of people working the cliffs with Shear on this day, came across a flat rock bearing the small imprint of an ancient millipede curled i nto a circle. You could see its legs and the segments of its body.

The millipede becomes the topic of lunch discussion. It doesn't have the right structure. Maybe it's a new species. Afterwards, the team combs the shore looking for more. They try to match the colour of the rock - is it more red or more brown? Hou rs later, they give up.

Figure 2.

The problem with looking for fossils of animals is that there aren't many. You'll find about 1,000 plant fossils for every animal fossil. Why is no great mystery: compare the number of ants on your front lawn to the number of blades of grass there.

"Yes, it's frustrating," says Shear, looking up from his work.

But he doesn't stop. Instead, he and the other paleontologists move to a different spot called Second Creek. They straddle a stream and begin sifting through a thin layer of brittle shale. He has more luck here, finding fragments of something that h e will analyze later.

Shear - who is here with North Carolina paleontologist Pat Gensel and New Brunswick Museum paleontologist Randy Miller - is scouring the shores and cliffs of the Bay of Chaleur working on a theory.

It goes like this: maybe, 390 million years ago - during what geologists call the lower Devonian Period, as plants began a huge burst of evolution and little multi-legged things scurried about the land - maybe insects didn't eat live plants. Maybe al l the hard-shelled creatures ate only dead plants or other creatures.

To understand how different Shear's theory is from the world today, you have to realize that almost all the insects you know - ants, aphids, caterpillars, grubs, and grasshoppers - eat live plants. If he's right, then sometime in the last 300 million years, insects took a radical turn in their evolution.

"There is still a lot of contention about this," he notes.

Two pieces of evidence support this theory. The first is that plant remains recovered from Devonian rocks reveal the presence of phenol, a chemical poisonous to small insects - or anything living, for that matter. The second is that there are no signs of plant-eating animals in these rocks.

Figure 3.

There are millipede-like animals, which, like millipedes today, were thought to eat dead and decaying plant matter. Then there are larger animals, like scorpions, which researchers believe, ate other animals - much like modern scorpions. No one has f ound traces of any animal that was the right size or had the right chewing mouth parts to be a plant-eater.

So at Gensel's suggestion, Shear came to the Chaleur cliffs seeking more proof. In the past, minuscule remnants have turned up in the rocks of Britain, Scotland and Germany, but nothing like this. Sometimes they find imprints - like little pictures o f what died - and sometimes preserved pieces of the shell, always less than one millimetre long. Until they came to New Brunswick, they had never found both in the same place. Something about how the rocks are formed at Chaleur made this spot different.

At the time these cliffs were created, there was probably a huge range of volcanoes spewing ash all over the place somewhere off what is now the Atlantic coast. Rains and rivers washed the ash down from the foot of the mountain to the mouth of a great river, where it settled to the bottom, entombing everything below. The mouth of that 390-million-year-old river became the cliffs along the Bay of Chaleur from Dalhousie to Atholville.

At the same time, a number of the major plant groups were starting to emerge. As the ash covered the plants, the rocks become a record of life.

So now as Shear walks along the cliffs near Dalhousie Junction, he looks for signs, clues and hints that he may be right - or wrong - about plant-eating insects.

He finds something: a small smudge of black on a small brown rock.

"That looks like an animal," he says, squinting at the rock. Taking out a lens about the size of a dime, he examines the smudge more closely. He claims there are faint signs of a pattern, a bumpy surface - the sort of bumpy surface that's all but inv isible until you've examined a few thousand or so of these smudges. Convinced it is something, Shear puts the rock aside, wrapping it in tissue.

Months later at his lab in Virginia, Shear will use acids and other chemicals to get rid of all but the smudge. Then, using a microscope, he will look at the remains of the tissue, 390-million-year-old cells.

Last year paleontologist Pat Gensel struck it rich. She found fossil fragments of 390-million-year-old scorpions, millipedes and arthropleurids.

Figure 4.

Shear recovered one piece of ancient scorpion lung and an entire millipede more than 10 millimetres long. Most of the pieces found before now are tiny by comparison.

The animals turn out to be the oldest land animals ever discovered in North America. Just as important as the size of the fossils is the fact that the New Brunswick material provides another example of animals from this time period. But still nothing that probably ate plants.

While Shear looks for animal smudges, Gensel - here with her husband and daughter on what has become an annual working vacation - hunts for plant smudges. The kind of smudges showing that plants were larger, more developed and diverse than previously believed.

So when she uncovers a slab of rock revealing an extensive mapwork of a single ancient plant, she gets excited. As she clears layer after layer of overburden, she finds more and more of a plant called Loganophyton.

When she has uncovered more than a square metre, she has a sudden thought. "How am I going to get this home?"

There are tougher dilemmas - such as finding nothing worth taking home. Here, Gensel has a virtual embarrassment of riches. Things that aren't interesting are left to erode on the beach. But some sites are so good that the Gensels use high-tech satel lite navigation systems to pinpoint their location so they can find them after winter takes its toll on the cliffs.

Figure 5.

The rocks here contain wonderfully preserved pieces of the plant, not just its image.

"Under a microscope, it looks like cuticle from a plant you went out in the garden and picked - except it is 380-million years old," says Gensel.

Decades of work by Gensel and her predecessors have turned up more than 23 groups of plants here. That's one-and-a-half times more than has been found in any other location in the world.

These are not plants you would know. None of them exists anymore. But Gensel believes they were the ancient forerunners of plants with seeds that exist today.

The most recent find, to be described in a journal next year, will be Forania plegio spinosa. Not exactly a household name, but if you lived in Dalhousie you might recognize it. It's named after Jack Foran, who used to be quite a hockey player at one time and whose family has rented the Gensels a cottage for most of the last 20 years. Pat Gensel thought naming an ancient plant after them would be a fittingly permanent thank you.

The names of several new species found in this area make similar references. There is Psilophyton forbesii, named after cliff-scouring University of Maine paleontologist Bill Forbes. Chaleuria, Loganophyton, and Oocampsa are so different from anythin g found anywhere else in the world that they may just force biologists to modify their theory of plant evolution. Gensel says the plants show structures that weren't thought to have evolved this long ago.

It won't be the first time fossils from these rocks have significantly contributed to a change in thinking about plant evolution. There was a time when scientists believed plants with seeds evolved from ferns (which have spores but no seeds). But ove r the last 20 or 30 years, the rocks of Dalhousie have helped convince most scientists that plants with seeds likely evolved separately.

And this year, months after returning to her lab at the University of North Carolina at Chapel Hill, Gensel has come to the conclusion there will be more to add.

This year alone, she has found one new species and two entirely new groups of plants. One, a tiny fossilized thing just a few millimetres across, is extremely interesting to Gensel. It has no name yet, but it shows a layered leaf structure, even thou gh fossils this old shouldn't have leaves.

She and other paleobotanists are still trying to determine how and when leaves first developed and when they first exhibited the modern layered structure. Leaves today have three distinct layers with different structures.

Most of the plants in the lower Devonian had what Gensel calls "emergences," coming out from the main stalk. These look like a cross between thorns and the stub of a branch, but probably acted as primitive leaves, collecting sunlight and turning it in to food for the plant. But fossils from Dalhousie and China are both showing more and more indications of early leaves.

"This is really going to clarify things," she says. Combined with the Chinese finds, they may help nail down when plants developed leaves, and more about how.

But Gensel isn't the only one happy with the summer's field work.

Excavating hard mudrock from what they believe was once a quiet, silty backwater, the New Brunswick Museum's Miller and Saint John geologist Jeff McGovern have uncovered what looks like one-third of a 380-million-year old shark.

The pieces are so well preserved that people will be able to tell more about shark evolution, says Miller. Early sharks were thought to have lived in the southern hemisphere and migrated north. Miller's find in these northern rocks may show they were here much sooner than once believed.

And then there are the teeth. Modern sharks have rows of teeth embedded in a fibrous membrane, a trait most shark biologists believe was a later adaptation. But the shark found in Campbellton had its jaw intact with rows of teeth.

All this from a line of cliffs running from Atholville to Dalhousie.

Figure 6.

The rocks from southern New Brunswick also have a place in evolutionary theory. Not because the formation's fossil is particularly large or unique, but because of history.

Saint John County offers a tremendous diversity of life and rock ages packed into a relatively small area. In the space of a few miles, you span hundreds of millions of years of evolution, explosions of life and massive extinctions.

As North America developed, constant folding and faulting created strips of rock running through Southwestern New Brunswick.

That geological variety makes Southern New Brunswick one of the places where paleontologists can examine the diversity of life over the ages - and they have. The same rocks fascinated amateur paleontologist George Frederic Matthew 100 years ago and en thrall New York geologist Ed Landing today.

In Saint John, outcrops of Pennsylvanian rock (286 to 320-million-years-old) with beautifully preserved specimens of prehistoric flies and ferns lie right next to Precambrian formations that are almost 300-million years older.

Not too far away, in St. Martins, are some small outcrops of Triassic rocks - the youngest in the province - showing footprints of early reptiles. By the time these rocks were being formed at the bottom of the Bay of Fundy, the first dinosaurs were ap pearing on land.

If dinosaur remains are ever found in New Brunswick, it will be here. A thick slice of Triassic geology breaks the surface at Parrsboro, N.S. - now famous for its dinosaur footprints. But only the thinnest slivers appear on the New Brunswick side.

Another southern New Brunswick formation that has attracted interest in the Saint John Group, a ribbon of Cambrian rock running from Reversing Falls in Saint John east to Hanford Brook.

Figure 7.

In these rocks, a host of trilobites - early arthropods, now extinct - were first found, as were small, shelly animals called ostracods.

The rocks of the Pre-Cambrian are almost devoid of fossils. In the early Cambrian there are traces and signs of soft-bodied animals: track marks and fossilized worm burrows.

But then in the 45 million years of the Cambrian period, every major group of animals with hard parts appears in the fossil record, from early chordates to arthropods.

In evolutionary terms, this is an explosion.

This Cambrian Explosion is still being explored in the rocks of southern New Brunswick. Along Hanford Brook, north of St. Martins, one can witness the "sudden" evolution of life: from trace fossils to small, shelly imprints to small trilobites and, e ventually, giant trilobites a foot wide.

Earlier this year, when English paleontologists David Siveter and Mark Williams published a paper describing a new - albeit extinct - group of minute shelly arthropods, they referred to fossils recovered in Hanford Brook as long ago as the 1800s and as recently as a few years ago.

Figure 8.

Just as intriguing as the explosion is the absence of fossils in the Precambrian, one of paleontology's great mysteries.

Evolutionary biologists believe that before the Cambrian Period, there was an increasing amount of oxygen released into the environment. Oxygen has long been thought to limit animals' size and structure. Low oxygen content in the water might require animals to have large surface areas to improve oxygen exchange through the skin. But as dissolved oxygen levels rose, animals could get smaller, develop different methods of obtaining oxygen and develop hard shells for protection. And it is not just evol utionary theory that benefits from the fossil record.

Fossils also offer some clues in the search for mineral resources such as coal and oil. Finding Pennsylvanian age plants may be a key to coal deposits, while finding fish may point to underground oil reserves. Geologists also look to fossils for clues to work out the age of rocks and to try to relate rock formations in different parts of the world.

Figure 9.

In fact, a team of world experts arrived in Saint John in August to explore the Saint John Group of Cambrian rocks.

Their task: to examine the world's major Cambrian rock formations, connect them and try to come up with a standard dating system to establish when the Cambrian age began and ended.

One of those Cambrian experts was New York State geologist Ed Landing. Along with the museum's Miller, Landing and Brock University's Steve Westrop led the tour of the Cambrian formations. Few know it better. Landing has been making yearly visits to t he Port City's rock outcrops for more than a decade.

He's working on a theory. Geologists believe the continents are afloat on a sea of lava, and that they move and crash into each other creating mountain ranges.

Landing thinks that modern New England, New Brunswick, Cape Breton, Newfoundland and England were once all part of single Cambrian age micro-continent he calls Avalon, separate from what is now North America.

His efforts to match rock formations and fossils in these areas has brought him to Hanford Brook and Forest Hills. If, 500 million years ago, these rocks were formed as part of the same land mass with the same environment, they should contain the same fossils.

One of the outcrops Landing and Miller took the experts to was the rock cliffs bordering the Mackay Highway. There, as hundreds of cars zipped through Saint John, the Avalon team pored over images of 500-million-year-old jellyfish-like animals.

Since most fossils are of animal bones or shells, finding a fossil of something boneless like a jellyfish is rare. But they are there, in plain view - if you know which roundish bulge you're looking for, that is.

"It is one of the best soft-bodied fossil sites in North America," says Randy Miller of the Saint John site. University of New Brunswick paleontologist Ron Pickerill agrees.

Pickerill has spent much of his career teasing clues to the past from the trace fossils - the footprints, dragmarks and worm burrows - trapped in the region's rocks.

He believes Saint John's jellyfish fossils are one of the best arguments for laws protecting fossils. Around one of the fossil jellyfish are a series of chisel marks, traces of a rogue collector. It's fortunate that invertebrate fossils aren't worth much money and that these jellyfish are suspended in unbelievably hard rock in a very public place.

But unlike the cliffs of Campbellton and the hills of Saint John, there are places that are relatively untapped, that may reveal even more about life in the distant past.

These rocks are, for the most part, the province's youngest, dating from Pennsylvanian or upper Carboniferous period some 286-million to 320-million-years ago. They are also, along with the Mississippian or Upper Carboniferous-period rocks of the Albe rt Formation, relatively unexplored by paleontologists.

In the rock outcrops near Norton, exposed by new highway construction, are the remarkably complete fossils of early bony fish. From the highway, travellers can see, preserved in the rocks, the remains of the rippled sand from the bottom of a great inl and lake. In his work in the area, Miller has found five complete fish as well as jumbles of fish bones embedded in rock.

What these fossils will tell us about the development of fish has not yet been determined, but Miller believes it will be significant - and only the beginning.

A huge chunk of the province, in a giant pie-slice from Sackville to Fredericton to Bathurst, contains these Carboniferous rocks.

Figure 10.

And there is reason to believe that somewhere in those rocks are fixed some ancient four-legged amphibians, the museum curator says. Some of the first tetrapods - that's Latin for four-footed - have been found across the Bay of Fundy in Joggins.

The same Pennsylvanian rock formation that juts out at Joggins dips under the Bay of Fundy and covers most of New Brunswick. Most of that rock is covered by dirt and trees except in outcrops near streams, along the coast and where road engineers have blasted their routes through the rock.

But unlike the Chaleur Shore and Saint John's Cambrian rocks, few people have taken a strong interest in New Brunswick's Pennsylvanian geology. It's just the way things are in this field, says Miller. Joggins is a good formation, so researchers go the re - they don't need to trek around New Brunswick seeking sites that may or may not be better.

So until someone finds something that knocks people's socks off, those New Brunswick sites may remain untapped.

After all this, it may be difficult to determine where New Brunswick fits in the grand scheme.

Perhaps it's best to think of the theory of evolution as a giant jigsaw puzzle where no one knows what the picture looks like and the pieces fit in a host of different spots.

You uncover a piece, look at it, decide what it is and then find a place for it. Sometimes you're right and sometimes you find out later that you're wrong and you have to go back and remake parts of the puzzle. It's an ongoing process.

But if you take a few of those puzzle pieces and turn them over, they may just say: "Made in New Brunswick."

Many of the fossils described in this story can be seen in the New Brunswick Museum's geology gallery 'Our Changing Earth,' located at One Market Square, Saint John, New Brunswick. The museum also has other exhibits featuring natural scie nce, history, fine and decorative art. For more information about the museum call (506) 643-2300

For information about palaeontology in New Brunswick write or call

Randall F. Miller, Ph.D.,
Curator of Geology and Palaeontology,
Steinhammer Palaeontology Laboratory,
New Brunswick Museum,
277 Douglas Avenue,
St. John, NB CANADA E2K 1E5
(506) 643-2361
* All photographs in this article courtesy of the New Brunswick Museum.