From Wells and Huxley’s The Science of Life (1929): It is difficult to imagine this world with all its land surfaces lifeless; yet for more than a half of it

From Wells and Huxley’s The Science of Life (1929): It is difficult to imagine this world with all its land surfaces lifeless; yet for more than a half of its history Life played out its drama under water, and the continents were practically barren. They were stark and bare, starker and barer than the utmost desert of today. Over the bare cliffs and desolate plains the sole breath of movement came from the wind and rain. A certain margin there may have been of faintly vitalized soil. From comparatively early times, a few simple algae may have trailed their filaments over the seashore or the moist borders of rock pools, or a few bacteria invaded the crumbling earth surface... The face of the land was like nothing we know today. There could have been no real soil, for soil is largely a product of plant action. There was no carpet of plants and felt-work of roots to hold water like a sponge, preventing rapid run-off, and to blanket the ground from excessive gain and loss of heat; and so the work of frost and wind, rain and sun, was much more active. The heights of the land were worn down quicker and sediments more actively deposited, and the scenery was more angular and forbidding. Even long after the first appearance of land-plants vast regions of the land which would now be covered with vegetation remained desert or semi-desert, since all the earliest plants demanded a good deal of moisture. Plants like grasses, which can thrive on dry steppes and prairies, are comparatively modern things. The Paleozoic Era knew nothing of them and the Mesozoic comparatively little. There was a desert flora and fauna in the Triassic; but possibly at least, the regions it inhabited would today be steppes or savannahs. It is a good exercise of the scientific imagination to picture this desolate and desert earth, its continents cyclically rising out of the waters and submerging themselves again, occasionally undergoing a spasm of mountain-building or an ice age, but remaining essentially lifeless for well over five hundred of our million-year periods, in spite of the abundant presence and notable progress of life in the waters. Through all these ages, the lands remained unconquered and must have seemed unconquerable.