Imagine: June 21, 1883, somewhere north of the Milk River, North-­West Territories.

Eight hundred and ten . . . eight hundred and eleven . . . eight hundred and twel– erk! Joe’s left foot sinks beneath him. He peers through the bug netting that swaddles his face. Ahead, reeds glisten in the pale green buffalo grass. His boot makes a sucking noise as he pulls it up for the next step. Another miserable swamp! And this country is supposed to be desert. At least that’s what Captain Palliser’s old map says: “No water. High level plain.” But it has poured rain almost every day of the two weeks Joe has been in this Canadian corner of the Great American Desert, and his map ­doesn’t show this shallow gully that he has been following for hours because he’s making a new map, measuring it step by step, one thousand Roman paces to the mile. You’d think the Geological Survey of Canada would use an odometer, but no, he’s a lowly assistant on his first expedition, and his boss, Dr. George Mercer Dawson, says making a pace survey for twenty miles in the stifling heat is a rare educational opportunity.

Joe is sweating so hard his glasses are fogging up. He tugs impatiently at the cord fastening the netting around his neck and flings it back; a corner of the net catches on his glasses and sends them flying over his head. He wheels, but where he had seen tufts of new grass and slim reeds and earth stained white with alkali, he now sees a flat, fuzzy carpet of indeterminate ochres and greens. He squints to catch a glint of sunlight on glass, but the sky is a dull, monochrome grey.

Joe kneels and crawls, groping with outstretched hands, until he has covered a circle within a twelve-­foot radius. No glasses. Here he is, in the middle of nowhere, and he ­can’t see! He gropes in his pocket for his compass. At least he can read it well enough to find his way to the expedition’s new camp, if the camp is where it is supposed to be — but what if the tents are hidden away in a thicket down by a creek? The prairie here is said to be gouged by deep gullies, called coulees, that you almost tumble into before you see them. How can he walk through this strange country when he ­can’t see where he’s going? And if he leaves, he’ll never find his glasses. A blind geologist.

Joe sits and waits. He’s been in this predicament before. Some­one is bound to come for him. The Survey ­can’t simply leave him to rot on the prairie. He can visualize the headlines: brilliant young ontario scientist lost in north-­west. survey director blamed. They ­won’t want his skeletal remains to be found a year or two from now, gnawed by animals and bleached as white as the buffalo skulls he saw piled up at the end of the Canadian Pacific Railway tracks at Maple Creek. Joe has read about grizzlies, and wolves, but he’ll likely die of hunger first. He has a few frogs and leeches for company, but they ­aren’t any more edible than the blackbirds’ eggs he has collected as specimens. The brackish water is drinkable, though he’ll shit his guts out later.

It feels pleasant to rest his aching feet. He rummages in his inside pockets for his pipe and tobacco pouch. A smoke will calm his nerves and keep the mosquitoes at bay. It might even attract some Indians. They ­aren’t far away. He saw a crowd of them at Maple Creek when he got off the CPR boxcar, cocooned in their bright striped blankets, feathers and quills and bits of fur sticking out of their long black hair, staring at the steam engine just like the folks did back home in Weston.

Joe ties his handkerchief to the end of his shotgun and props it up as a signal. A light rain is falling, and even on this bare plain he’ll be hard to spot in the drizzle. He has dreamed of exploring the Great Lone Land since he was a kid at school staring at the blank space on a map of the North-­West over which the cartographer had scrawled “Buffalo Run.” Now here he is, but the Indians say Mother Earth has swallowed the buffalo. There are other explanations for the herds’ disappearance — the railroads, mass slaughter — but still, it is an enigma.

To the west, above the sloping banks of the coulee, the prairie horizon is shrouded in mist. Joe feels submerged, as if he’s sitting at the bottom of a pond. He is, in a way. Not a pond, but a sea, a dried-­up tropical sea that covered this part of North America hundreds of millions of years ago. The land he is sitting on was lower then, and enough fossils have been found in the dry rocks to prove that this ancient sea teemed with shelled creatures unlike anything living in the world today. Joe finds fossils unbearably boring; he prefers to imagine these stony carapaces pulsating, brilliantly coloured, wriggling and burrowing and squirting, paddling along with their hairlike legs, antennae waving, eyes and mouths gaping, closing, tentacles probing among corals and sponges and seaweeds waving in the lazy current. Jellyfish too, giant worms, and translucent blobs, half plant, half animal. What a genius Darwin was to perceive that all life may have begun as a single primordial organism.

About eight miles to the southwest, in a blossoming choke­cherry thicket on the bank of a nameless creek, Thompson, the expedition’s cook, and Graydon, the wagon driver, are cleaning up after lunch. A few mouthfuls of salt pork and bannock simmer in the skillet. The kid should’ve been here long ago. It’s time to move on.

From the Hardcover edition.