Even though she was just as battered and half drowned as before, Roamer felt suddenly better. If she had been left alone it would have been the most unbearable thing of all; the presence of others was comforting. But still, these others were not her family, not her troop.

More displaced vegetation coursed over the surface of the river, clustering along its spine where the water ran deepest. There were more trees and bushes, some of them washed by this precursor of the Congo thousands of kilometers downstream from the very different lands in the center of the continent. There were animals here too. Some of them clung to the floating foliage, like the anthros. She saw the flitting, nervous forms of a couple of crowders, and even a potbelly, sitting squat on the trunk of a walnut. The potbelly, a female, had found a stable place to sit, and the rain didn’t bother her. She had already resumed her usual habit of feeding on leaves conveniently delivered to her clutching hands and feet.

But not all the animals in this gruesome assemblage had made it here alive. There was a whole family of fat, piglike anthracotheres, all of them drowned, stuck in the branches of a broken palm like meaty fruit. And the huge indricothere that had been washed into the river just before the fall of the mango was here too, a great carcass drifting in the water, long neck lolling back and powerful legs splayed, just another bit of floating detritus jammed in with the rest.

Gradually, as the river broadened, the subtle currents shoved these fragments together, foliage and roots tangling, and a makeshift raft assembled itself. The animals stared at one another, and at the churning river, as their crude vessel drifted on.

Roamer could see the forest, growing thick and green on shallow riverbank slopes of eroded sandstone. The trees were mangos, palms, a kind of primitive banana. Branches hung low over the water, and lianas and vines looped over the tangled terraces. Her arms ached for a branch to swing from, a way she could climb from here to there. But the forest was separated from her by churning water — and as the vegetable raft continued to sail downstream, those tempting banks receded further, and the familiar forest gave way to the mangroves that dominated the coastal areas.

The rain wasn’t done yet. It actually fell harder. Fat droplets hurled themselves out of the leaden sky. The water was stippled with craters that disappeared as soon as they were formed. A white-noise harshness flooded her ears, so that it was as if she were lost in a kind of huge bubble of water, water below and around her, with only this broken mango to cling to. Moaning, chilled to the bone, Roamer burrowed into the branches of the mango and huddled, alone, waiting for everything to go away, and for her to be returned to the world she knew, of trees and fruit and anthros.

That, however, was never going to happen.

The storm, heavy as it was, blew itself out quickly. Roamer saw finger-thin shafts of light pushing into her shelter of foliage. The rain noise had gone, to be replaced by the eerily soft lapping of water.

She struggled out of the branches and clambered on top of the tree. The sun was strong, as if the air had been cleared, and she felt its warmth sink deep into her fur, drying it quickly. For a heartbeat she luxuriated in the warmth and dryness.

But there was no forest here: only this fallen tree and its cluster of broken companions, drifting over a gray-brown sheet of water. There weren’t even any riverbanks. On three sides of the tree, all she could see was water, all the way to a knife-sharp horizon. But when she looked back the way the raft had drifted, she spotted land: a line of crowded green and brown, striped over the eastern horizon.

A line that was receding.

The raft of debris had been washed out to sea, out into the widening Atlantic, anthros, potbelly, crowders, and all.

After the days of Noth the geometry of the restless world had continued to evolve, and it continued to shape the destinies of the hapless creatures who rode the continental rafts.

The two great cracks that had doomed ancient Pangaea — the east-west Tethys Sea, and the north-south Atlantic Ocean — closed and opened respectively. Africa was undergoing a slow collision with Europe. Meanwhile India was drifting north to crash into Asia, and the Himalayan Mountains were being thrust into the air. But immediately after the young mountains were born, the rain and the glaciers had begun their work, gouging and eroding, washing the mountains back to the sea: On this turbulent planet, rock flowed like water, and mountain ranges rose and fell like dreams. But as the continents closed, the Edenic flow of the Tethys was doomed, though fragments of the shrinking ocean would survive as the Black, Caspian, and Aral Seas, and in the west as the Mediterranean.

As the Tethys died there was a great drying, right across the belly of the world. Once there had been mangrove forests in the Sahara. Now a great belt of semiarid scrub spread around the old track of the Tethys, across North America, southern Eurasia, and northern Africa.

Meanwhile, the huge land bridge that had closed off the northern Atlantic, spanning from North America to northern Europe via Greenland and Britain, was being severed, and the Atlantic reached up to the Arctic Ocean. As the ancient east-west ocean passage was being closed, so a new channel from south to north was opening.

Thus ocean currents were reshaped.

The oceans were great reservoirs of energy, restless, unstable, mobile. And all the oceans were laced with currents, great invisible Niles that dwarfed any river on land. The currents were driven by the sun’s heat and the Earth’s rotation; the top few meters of the oceans stored as much energy as the whole of the atmosphere.

Now the huge equatorial currents that had once rolled around the Tethys belt were disrupted. But already the great flows that would dominate the widening Atlantic were in place: A precursor of the Gulf Stream flowed, a mighty river sixty kilometers across, running south to north with the force of three hundred Amazons.

But this change in circulation patterns would reconstruct the planet’s climate. For while equatorial currents promoted warming, north-south interpolar currents provoked a vast refrigeration.

To make matters worse, Antarctica had settled over the Earth’s southern pole. Now its great ice cap had begun to gather, for the first time in two hundred million years. Vast, cold circumpolar ocean currents gathered in the southern seas, feeding the great northward currents of the Atlantic.

It was a crucial change: the start of a mighty planetary cooling, a downturn of the graph, that would persist to human times and well beyond.

All over the planet, the old climate belts shrank toward the equator. Tropical vegetation types survived only in the equatorial latitudes. In the north, a new kind of ecology appeared, a temperate woodland of mixed conifers and deciduous trees. Vast swaths of it covered the northern lands, stretching across North America, Europe, and Asia from the tropic to the Arctic.

This climatic collapse triggered a new dying — what paleobiologists would later call the Great Cut. It was a drawn-out, multiple event. In the ocean the plankton population crashed repeatedly. Many species of gastropods and bivalves disappeared.

And on the land, after thirty million years of comfortable success, the mammals suffered their first mass extinction ever. Mammalian history was cut in half. The exotic assemblages of Noth’s times finally succumbed. But new, larger herbivores began to evolve, with heavy-duty ridged teeth able to cope with the new, coarser vegetation typical of seasonal woodland. By Roamer’s time the first proboscideans, properly equipped with trunks and tusks, were already walking the African plains. The trunk, unparalleled for muscular flexibility save for an octopus’s arm, was used for stuffing the animal’s mouth with the vast quantity of food it needed. These deinotheres had stubby trunks, and odd, downward-curving tusks that they used for stripping the bark from trees. But, unlike their moeritherium ancestors, they looked like elephants, and some already grew as tall as the African elephants of later times.