The Long Earth

leaving scant traces in the fossil record; only on the Datum will you find bones to illustrate the slow plod towards mankind.’
    ‘What does it mean, Lobsang? That was Nelson’s question. What is the Long Earth
for
?’
    ‘I suppose that’s what we came out here to find out. Shall we proceed?’

33
    ON THEY SAILED , leaving the intricate humanoid community far behind. They were travelling east for now, away from the Pacific coast and back into the interior of the continent.
    And, almost unobserved, they passed another milestone: a million steps from Datum. There was no dramatic change, no new perception, only the silent turning-over of a new digit on the earthometers. But now they were in the worlds the wavefront pioneers called the High Meggers. Nobody, not even Lobsang, knew for sure if anybody had actually stepped this far before.
    The jungle that clad North America gradually grew thicker, denser, steamier. From the air you saw little but a green blanket, punctured here and there by scraps of open water. Lobsang’s aerial surveys suggested that in these worlds there might be forests all the way to the ice-free poles.
    As before, every day Lobsang paused to allow Joshua down to explore, and stretch his legs. Joshua would find himself in a dense forest of ferns of all sizes, and trees both unfamiliar and familiar, strung with climbers like honeysuckle and grapevines. The flowers were always a riot of colour. Some days Joshua came back with bunches of grape-like fruit, small and hard compared with domesticated varieties of grape, but still sweet. The dense forest inhibited the growth of large animals, but there were strange hopping animals, a little like kangaroos but with long flexible snouts. Joshua learned to trust these creatures, whose trails, cleared through the undergrowth, led reliably to open water. And he saw aerial creatures in the canopy itself. Giant flapping wings. And, once, a flopping, squirming thing that looked for all the world like an octopus, spinning like a Frisbee through the canopy trees. How the hell had
that
got there?
    He spent a couple of nights outside the ship, just for old times’ sake. It was almost like his sabbaticals, especially if he stepped a world or two away from Lobsang, but his lord and master didn’t approve of that. Still, when he got the chance he would sit by his fire, listening for the Silence. On a good night he thought he could feel the other Earths, vast empty spaces all around him, just beyond the reach of his tiny circle of firelight. Untold possibilities. And then he would climb back up to the airship, leaving behind a whole world with its own unique mysteries barely examined.
    On they would travel, to another, and another yet.
    And then, after fifty days, more than one and a third million worlds from home, the land and air seemed to shimmer, and the forest melted as the worlds cleared away, to reveal a sea that stretched to the horizon, foam-flecked and glimmering, at the heart of North America.
    Still stepping, Lobsang turned the airship south, looking for dry land.
    On world after world the sea persisted, teeming with life, the green of algal blooms, pale white shapes that might have been coral reefs, and creatures that jumped and swam that might have been dolphins. Cautious dips to the water level proved that the sea was saline. That didn’t necessarily mean this American Sea was open to the wider world ocean; inland seas could become saline through evaporation. The water samples Lobsang retrieved were full of exotic seaweed strands and crustaceans – exotic to a specialist anyhow. Lobsang stored specimens and images.
    At last, heading south, they hit a coastline. Lobsang cut the stepping, and they inspected one particular world of this latest band, selected at random. They came to fog banks first, then huge bird-like forms swooping low over the sea, and then the land itself, where dense forest spilled almost all the way down to the shore. Lobsang thought that the higher land they were approaching might be some relative of the Ozark Plateau.
    From here they sailed east until they came to a tremendous valley, perhaps carved by some distant cousin of the Mississippi or the Ohio. They followed this north to an estuary where the river spilled into the inland sea. The fresh water pushing into the saline ocean was visible from a muddy discoloration that persisted miles out from the coast.
    And here, in the open, by the banks of the freshwater river, the