“Otherlands: A Journey Through Earth’s Extinct Worlds” by Thomas Halliday. New York: Random House, 2022. 385 pages, $28.99 (Hardcover).

In Richard Adams’ “Watership Down,” the rabbit Fiver is celebrated because he can count to five. Humans do a bit better, but most of our brains short out after a few thousand. Thomas Halliday begins his unfolding of Earth’s history with the usual attempt to make its 4.5 billion-year age intelligible. Compress all that time into one day, and three million years would elapse every minute. The dinosaurs’ extinction would come at 21 minutes to midnight, and written human history would occur in the last tenth of a second. In “Otherlands,” the author sets out to bring to life what happened during those immense temporal stretches, dropping in on a specific time and place during each period he covers and picturing the world as it was then – the climate, the landforms, the animals and, in fascinating detail, their interactions.

As a paleontologist, Halliday is at home with an amazing range of technical terms, casually rattling off thorny ones like Anthropornis nordenskjoeldi or palaeoscolecids. Fortunately, you can safely skim over these tongue twisters and focus on the big picture – 16 chapters reaching back from a mere 20,000 years in the past, when humans moved into the Americas, to the Ediacaran Period, 550 million years ago. Each chapter presents its own point in time in memorable fashion, homing in on everyday experiences to make that particular “otherland” come alive. Consider a representative passage from his chapter on the Cretaceous, about 150 million years ago:

The flattened shell and long neck and tail of an Ordosemys turtle draws circles in the mossy lake as little pterosaurs whir among the choking clouds of midges that now hang over the water, snapping them out of the air. Here a shimmering and iridescent dragonfly hunting wasps and horseflies on the wing. There a cluster of blood-red snails hang from plants like berries above the shallows. Above, sparrow-sized Eoenantiornis, “dawn-opposite birds,” scout for insects among the branches of a ginkgo, while the languid 7-metre wings of the pterosaur Moganopterus beat through the sky.

In Halliday’s hands you can just about feel the jungle heat of that vanished world, millions of years before hominids appeared. But there is nothing fanciful about his imagined landscapes. He’s too careful a scientist to invent details. The footnote at the end of the Cretaceous passage just cited links to five articles in specialist journals. It would take an intrepid reader to follow up on all the references in the book’s 44 pages of notes, but just their extent shows the depth of the author’s research, while every paragraph of the text demonstrates how thoroughly he has absorbed and synthesized all that learning.

Halliday describes his Cretaceous lake in vivid detail, but he is just as effective treating vast occurrences, such as the filling of the Mediterranean Sea. About five million years ago, a collision of tectonic plates opened the Straits of Gibraltar to the Atlantic Ocean, inundating the eastern Mediterranean. But the waters were stopped by a land bridge between North Africa and Sicily. In time this natural dam was breeched, creating a canyon though which water rushed at some hundred miles an hour and plunged into the eastern basin over a waterfall of 1,500 meters – half again as high as Angel Falls and immensely more powerful. Even so, it took more than a year to fill the eastern end of today’s sea.

Halliday is perfectly at home describing huge events like this or the impact of the Chicxulub Comet that ended the Cretaceous Period, plunging the world into years of darkness and killing off the dinosaurs (except the birds) and two-thirds of the tree species. But he may be even better with intimate details, like the unique chemical signatures the water-resistant wax of leaves impart to rocks and soil, allowing paleontologists to identify an area’s flora even after the plants themselves have vanished. He has a particular interest in synergy, the way organisms cooperate, so that a plant may absorb and perpetuate a fungus, say, and use it to harvest minerals from the soil while providing the fungus photosynthesized food. In time different organisms become wholly interdependent, as we ourselves are with the organelles that inhabit our cells, several of which retain their own DNA.

Of special note are the book’s maps tracing the elaborate dance of the world’s tectonic plates over time as continents formed and split, heaving up mountain ranges and broadening or narrowing seas and seaways. At one moment – the Devonian – Appalachia adjoined Ireland and Scandinavia while what would become Venezuela and Florida trailed as a peninsula at its southern end. At another – the Cambrian – almost all dry land was compacted into the southern supercontinent Gondwana and washed by a vast Panthalassic Ocean, uninterruptedly swirling around the North Pole. (A mind-boggling time lapse video of all this is available. Look for “YouTube history of the earth.”)

No one today can write the earth’s biography without considering our current global warming, changing weather patterns, deforestation, oxygen-depleted oceans and ever-spreading pollution. But even after giving these threats their due – rising sea levels alone directly threaten more than a billion people living in low-lying areas like Bangladesh or our own eastern seaboard – Halliday is guardedly optimistic. Life is already evolving to deal with the world we have created. New species of fungi and bacteria have learned to digest our plastic waste. If we can evolve too, as we seem already to be doing in turning away from fossil fuels and moderating global birthrates, we may regain our synergy with the natural world. “Change is inevitable,” he writes, “but we can let the planet take its own time, as we allow the shifting sands of geological time to lead us gently into the worlds of tomorrow.”

– Reviewed by Joe Glaser, Western Kentucky University English Department.

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