Authors: John Demont
It’s a staggering notion: when Pangaea formed, Nova Scotia was on or near the equator, and continued to inch its way northward as the supercontinent slowly broke apart and the continents continued to assemble. In time, as the continents collided, mountain belts formed—and, eventually, small deep basins between them. This mosaic of interconnected mountains and basins extended from central Nova Scotia northward across the Gulf of St. Lawrence to the present-day shore of the Gaspé Peninsula, east to Newfoundland. The region, by then completely emerged from the sea, was crossed by northeasterly flowing rivers. The rivers carried gravel, sand and mud from the adjacent primordial
mountains down into the luxuriant rainforest swamps and bogs flourishing across the tropical lowlands. As the climate warmed, vegetation formed, not just in present-day Nova Scotia but elsewhere in Pangaea’s spreading land mass. And ever so slowly, in the river valleys and freshwater lakes between the remains of those mountain ranges in what would become England and Wales, Pennsylvania, Virginia and Nova Scotia, coal formed.
What Calder seeks are the remnants of the vegetation that grew on the flood plains. The tectonic plates continued to grind, collide, recede and collapse, the continents to assemble. Rock bent into folds, or split, causing great slices of plate to rise and fall relative to each other. The Cumberland Basin, where Joggins lies, was one of the low-lying areas that settled between the faults. The exposed sediments we’re looking at are the 300-million-year-old wash from the rivers in the uplifted highlands to the west and south.
It doesn’t take Calder long to find what he’s after: a brownish column, maybe a yard around, suspended perpendicularly within the cliff face. All these hundreds of millions of years later, it’s still possible to make out elongated, diamond-shaped scars that span the trunk. Today, the tree’s only living relative is common club moss, which grows just a few centimetres high. In its heyday, that Lepidodendron, one of the most common types of lycopod, stretched thirty metres into the steamy prehistoric sky. Calder’s on a bit of a roll now, pointing out thin stems that indicate a once-thick undergrowth of calamites, ancient horsetails; running a finger along the remains of a cordaite, which had roots like today’s mangrove and metre-long leaves that resembled the amaryllis. Each remnant tells a similar story of the ancient crust of the earth sinking and sediment quickly—by geological standards—accumulating overtop.
Lyell and I have something in common. What he saw in 1842—Lepidodendrons suspended as if in aspic, lycopods haphazardly dotting the sedimentary rocks, calamites peeking out at weird angles—astounded him. “Just returned from an expedition of 3 days to the strait which divides Nova Scotia from New Brunswick,” he wrote to his sister after a Joggins visit similar to my own, “whither I went to see a forest of fossil coal—trees—the most wonderful phenomenon perhaps that I have seen, so upright do the trees stand, or so perpendicular to the strata, in the ever-wasting cliffs, every year a new crop being brought into view, as the violent tides of the Bay of Fundy and the intense frost of the winters here, combine to destroy, undermine, and sweep away the old one—trees twenty-five feet high and some have been seen of forty feet, piercing the beds of sandstone and terminating downwards in the same beds, usually coal.”
I have to tell you: it’s a humbling thing to look at the remains of a 300-million-year-old plant. The intricate, perfect design, for starters. Then there’s the notion I first encountered in Barbara Freese’s book
Coal: A Human History,
that when you look at an ancient fern you’re indirectly gazing upon prehistoric sunlight. All those ancient trees, ferns and mosses were sophisticated machines that captured solar energy, and converted it into chemical energy and carbon that stayed stored within their cells until they decayed, burned or got eaten. Usually, when plant material dies, it decomposes more rapidly than it accumulates. Peat, the precursor to coal, forms when the reverse is true—when the wetland has a waterlogged surface with little access to oxygen, and this protects the plant matter from bacteria, fungi and other organisms that cause decomposition.
Whether or not peat will form depends mostly on climate and geology. Precipitation has to exceed evaporation. The buildup of plant matter has to keep pace with the subsidence of the earth’s
surface, so sedimentary deposits or rising water levels don’t overwhelm the peat. Let’s assume optimum conditions. Beneath the ever-deepening layers of sand, silt and mud, most of the peat moisture is squeezed out. More heat and pressure furthers the transformation, first into lignite, a soft, brownish-black coal with a low carbon content, then black or bituminous coal, the type found in Nova Scotia and in most of the coal-bearing areas on the planet. A mineral that fuels economies, launches kingdoms and revolutionizes worlds.
Coal wasn’t the only rock formed in the Carboniferous—the name given by scientists to the period running from 360 million to 280 million years ago—world. Basins were subsiding, infiltrated by upland streams that deposited their coarse sand and gravel loads, covered by rising seas that eventually retreated, leaving coastal plains that were again colonized by peat-forming vegetation. The pattern—coal seams, flood-plain mudstones, lake or marine lime-stones and riverbed sandstones—is visible in outcrops around the world, and is thought to be linked to the rising and falling sea level as the ice caps of the South Pole melted and grew when the climate shifted. Nowhere, though, can match Joggins as a time-lapsed snapshot taken as the world’s great coalfields were being formed.
No wonder Joggins was so deeply embedded in Lyell’s thinking from that moment on. In 1852 he returned with another illustrious Nova Scotian scientist in tow. They had met a decade earlier, when Lyell made a brief stop before his trip to Joggins. In New Glasgow he dined at Mount Rundell, met the local mucky-mucks and paid a visit to a young man with a good fossil collection. “He looked over my specimens with appreciation,” John William Dawson wrote in his memoirs, “and listened with interest to what I could tell him of
the geology of the beds in which they occurred.” Dawson, twenty-two, devoutly Christian, fluent in Latin and Greek and with a working knowledge of Hebrew, was freshly back from Edinburgh, Scotland, after his university studies had been interrupted by a family financial setback. At that point his startlingly varied career—geologist, paleontologist, author, publisher, politician, educational visionary, university president—was just beginning. His life-altering epiphany, on the other hand, had already occurred. “It happened, when I was a mere schoolboy,” Dawson wrote, “that an excavation in a bank not far from the schoolhouse exposed a bed of fine clay-shale which some of the boys discovered to be available for the manufacture of home-made slate pencils.”
Dawson and his classmates used to amuse themselves by digging out flakes of the stone and cutting them into pencils with their pocket knives. One day Dawson was surprised to discover that one of the flakes “had on it what seemed to be a delicate tracing in black, of a leaf like that of a fern.” The riddle—real leaves or not, and if real, how did they come to be in the stone?—preoccupied his mind. Eventually his father sent him to the principal of a local grammar school, the astute Scotsman Thomas McCulloch. He “received me kindly, and assured me that the impressions were real leaves imbedded in the stone when it was being formed.” And Dawson’s life, quite simply, was never the same again.
He read everything he could get his hands on about geology and natural history. He began collecting the minerals, shells and fossils that he found in the Pictou County countryside and as far away as the petrified forest of Joggins. He expanded his collection by exchanging specimens with Gesner and other Nova Scotia geologists. At the University of Edinburgh he took courses in geology, taxidermy and the preparation of thin sections of fossil animals and plants for the microscope. Meeting Lyell was another turning point;
a friendship blossomed. Afterwards, Dawson went back to university and became British North America’s first trained geologist.
That made him perfect company when Lyell returned to Joggins. There, within the sediment-filled trunks of three ancient trees, they discovered what turned out to be the remains of one of the world’s earliest known reptiles—and the first evidence that land animals had lived during the coal age. Dawson named the discovery
Hylonomus lyelli,
after his mentor. The finding gave Lyell new ammunition against the catastrophists, and solidified his thinking that the planet’s rock layers served as an archive of earth’s evolution. What Lyell saw and concluded in Nova Scotia also had important implications in the greatest question of the day: evolution or creation?
Lyell’s geological theories were already a primary influence on the thinking of Charles Darwin, who had been presented with a copy of the first volume of his
Principles of Geology
before departing on the
Beagle
in 1831. Darwin would lean heavily upon the lessons from Joggins in making the case for evolution in
The Origin of Species:
In other cases we have the plainest evidence in great fossilized trees, still standing upright as they grew, of many long intervals of time and changes of level during the process of deposition, which would not have been suspected, had not the trees been preserved: thus Sir C. Lyell and Dr. Dawson found carboniferous beds 1,400 feet thick in Nova Scotia, with ancient root-bearing strata, one above the other, at no less than sixty-eight different levels. Hence, when the same species occurs at the bottom, middle and top of a formation, the probability is that it has not lived on the same spot during the whole period of deposition, but has disappeared and reappeared, perhaps many times, during the same geological period.
Lyell, in fact, changed Darwin’s whole world view. As he was quoted as saying, “The greatest merit of the Principles was that it altered the whole tone of one’s mind, and therefore that, when seeing a thing never seen by Lyell, one yet saw it through his eyes.”
Since the tide is in, we don’t see any stumps when we walk past the spot where Lyell and Dawson made their world-altering discovery. Otherwise, the scene is pretty much the same as it was 155 years ago. It gives me a familiar buzz. Like most people, I’ve often felt that I was born in the wrong time and place. There was my Alexandre Dumas phase, when I felt I should have had buckler and sword on my hip, a great cape trailing behind me, as I strutted through the rain-slicked streets of Paris. There was a period when I felt terribly cheated because I hadn’t been at Minton’s in New York in the 1940s, to hear Charlie Parker shoot bolts of lightning from his alto sax in situ rather than on vinyl. Nowadays I am more inclined to want to be one of those Victorian amateur scientists, those self-educated, restlessly inquisitive polymaths tromping around in their tweeds, with butterfly nets and microscopes, waiting for the flashes of insight that seem responsible for most of the scientific advances of the age.
Calder, an accomplished documentary photographer, seems to fit easily into the mould of the universal man. So did Lyell, a lawyer by profession but dedicating himself to the great questions of existence, and Gesner—notwithstanding the flawed personality that destined him to die broke and broken—with his eternal curiosity. Most of all I wanted to be like Dawson, but not when he was changing the world with Lyell. I preferred to imagine him, sketchbook in hand, prospector’s hammer in a bag slung over his shoulder, making his way from one end of Nova Scotia to the other, whether working
as a geologist or as the province’s first superintendent of education, which involved meticulously visiting every school in every district.
Dawson was mad for rocks; he couldn’t help himself, even though it nearly killed him. A trip he made one April, while trying to get to the root of the province’s educational woes, was perhaps illustrative: travelling over the North Mountain in the Annapolis Valley in a light snowstorm, addressing an educational meeting in “that somewhat isolated locality,” then convincing local fishermen to take him at daybreak through heavy seas to see a large fall from a cliff a few miles down the coast. Amidst the debris he found “an amazing quantity of fine zeolites with which we loaded the boat and returned to Black Rock in time to pack the specimens before breakfast.” Then he left for Aylesford, twenty-five miles away, before continuing west to picturesque Digby Neck. He took the ferry to Long Island, “on which no conveyance was to be had.” There he walked the island’s entire ten-mile length, examining rocks as he went.
Dawson travelled mostly by horse, whether riding or via stagecoach, sometimes by boat or on foot, and, as he put it, “my educational and geological journeys were therefore not only attended with much labour, but occasionally with some risk.” If you want to understand the extent of Nova Scotia’s coalfields, it’s instructive to see things through his eyes. To consider, for a moment, the awe he may have felt traversing the land near Sydney, on Cape Breton Island, where he was transfixed by fossilized rain marks—“the finest example yet known”—and by shales he declared “also much more rich than those at the Joggins in the leaves and other more delicate parts of plants.”
Then there was the sheer immensity of the Sydney coalfield, within which thirty-four coal seams had by then been identified. At that point Dawson wouldn’t have precisely understood how slowly the transformation of ancient wetlands into energy source
occurred. Peat, we now know, accumulates gradually, growing only four millimetres a year in the modern tropics. A coal seam one metre thick was originally five to ten metres of peat, and took perhaps 2,500 years to accumulate; each of the coal beds of Joggins represents about 1,000 years of peat accumulation. By comparison, the coal seams of the Sydney coalfield, 4.3 metres at their thickest, were the product of roughly 10,000 years of natural history. Neither Dawson nor his guide, Richard Brown, the manager of the Sydney Mines, would have realized one key point about the formation. It would take deeper coal mines in the area, and the boreholes of offshore drill ships, to show that the coal-bearing rocks extend nearly to the south coast of Newfoundland. Fully 98 percent of the Sydney field is underwater.