All admit that the mountains of the globe are situated mostly along the border regions of the continents (taking these regions as 300 to 1000 miles or more in width), and that over these same areas the sedimentary deposits have, as a general thing, their greatest thickness. At first thought, it would seem almost incredible that the upliftings of mountains, whatever their mode of origin, should have taken place just where the earth’s crust, through these sedimentary accumulations, was the thickest, and where, therefore, there was the greatest weight to be lifted. … Earthquakes show that even now, in this last of the geological ages, the same border regions of the continents, although daily thickening from the sediments borne to the ocean by rivers, are the areas of the greatest and most frequent movements of the earth’s crust. (1866)
[Thus, the facts were known long ago; the explanation by tectonic activity came many decades later.]

Believe me, this planet has put up with much worse than us. It’s been through earthquakes, volcanoes, plate tectonics, solar flares, sun-spots, magnetic storms, pole reversals, planetary floods, worldwide fires, tidal waves, wind and water erosion, cosmic rays, ice ages, and hundreds of thousands of years of bombardment by comets, asteroids, and meteors. And people think a few plastic bags and aluminum cans are going to make a difference?

But no other theory can explain so much. Continental drift is without a cause or a physical theory. It has never been applied to any but the last part of geological time.

Continents are complexes of crustal scar tissue.

Even more difficult to explain, than the breaking-up of a single mass into fragments, and the drifting apart of these blocks to form the foundations of the present-day continents, is the explanation of the original production of the single mass, or PANGAEA, by the concentration of the former holosphere of granitic sial into a hemisphere of compressed and crushed gneisses and schists. Creep and the effects of compression, due to shrinking or other causes, have been appealed to but this is hardly a satisfactory explanation. The earth could no more shrug itself out of its outer rock-shell unaided, than an animal could shrug itself out of its hide, or a man wriggle out of his skin, or even out of his closely buttoned coat, without assistance either of his own hands or those of others.

I shall consider this paper an essay in geopoetry. In order not to travel any further into the realm of fantasy than is absolutely necessary I shall hold as closely as possibly to a uniformitarian approach; even so, at least one great catastrophe will be required early in the Earth's history.

If the fit between South America and Africa is not genetic, surely it is a device of Satan for our frustration.

In Ireland, there are the same fossils, the same shells and the same sea bodies, as appear in America, and some of them are found in no other part of Europe.

In the whole of geophysics there is probably hardly another law of such clarity and reliability as this—that there are two preferential levels for the world’s surface which occur in alternation side by side and are represented by the continents and the ocean floors, respectively. It is therefore very surprising that scarcely anyone has tried to explain this law.

It must have appeared almost as improbable to the earlier geologists, that the laws of earthquakes should one day throw light on the origin of mountains, as it must to the first astronomers, that the fall of an apple should assist in explaining the motions of the moon.

South America must have lain alongside Africa and formed a unified block which was split in two in the Cretaceous; the two parts must then have become increasingly separated over a period of millions of years like pieces of a cracked ice floe in water.

The forces which displace continents are the same as those which produce great fold-mountain ranges. Continental drift, faults and compressions, earthquakes, volcanicity, transgression cycles and polar wandering are undoubtedly connected causally on a grand scale. Their common intensification in certain periods of the earth’s history shows this to be true. However, what is cause and what effect, only the future will unveil.

The globe of this earth … [is] … not just a machine but also a organised body as it has a regenerative power.

The Newton of drift theory has not yet appeared. His absence need cause no anxiety; the theory is still young and still often treated with suspicion. In the long run, one cannot blame a theoretician for hesitating to spend time and trouble on explaining a law about whose validity no unanimity prevails.

The transition from sea-floor spreading to plate tectonics is largely a change of emphasis. Sea-floor spreading is a view about the method of production of new oceans floor on the ridge axis. The magnetic lineations give the history of this production back into the late Mesozoic and illuminate the history of the new aseismic parts of the ocean floor. This naturally directed attention to the relation of the sea-floor to the continents. There are two approaches: in the first, one looks back in time to earlier arrangements of the continents; in the second, one considers the current problem of the disposal of the rapidly growing sea floor.

The universe flows, carrying with it milky ways and worlds, Gondwanas and Eurasias, inconsistent visions and clumsy systems. But the good conceptual models, these serena templa of intelligence on which several masters have worked, never disappear entirely. They are the great legacy of the past. They linger under more and more harmonious forms and actually never cease to grow. They bring solace by the great art that is inseparable from them. Their permanence relies on the immortal poetry of truth, of the truth that is given to us in minute amounts, foretelling an order whose majesty dominates time.

The volumes, the surfaces, the lines—in one word, the structures that build a tectonic construction—do not represent the whole picture: there is also the movement that animated and still animates these bodies because the history continues and we live under no particular privileged conditions at any given time in this great process.

The Wegener hypothesis has been so stimulating and has such fundamental implications in geology as to merit respectful and sympathetic interest from every geologist. Some striking arguments in his favor have been advanced, and it would be foolhardy indeed to reject any concept that offers a possible key to the solution of profound problems in the Earth’s history.
Published while geologists remained sceptical of Alfred Wegener’s idea of Continental Drift, Though unconvinced, he published these thoughts suggesting that critics should be at least be open-minded. His patience was proven justified when two decades later, the theory of plate tectonics provided a mechanism for the motion of the continents.

Therefore, these [geotectonic] models cannot be expected to assume that the deeper parts of the earth’s crust were put together and built in a simpler way. The myth about the increasing simplicity with depth results from a general pre-scientific trend according to which the unknown or little known has to be considered simpler than the known. Many examples of this myth occur in the history of geology as, for instance, the development of views on the nature of the seafloor from the past to the present.

Though the theories of plate tectonics now provide us with a modus operandi, they still seem to me to be a periodic phenomenon. Nothing is world-wide, but everything is episodic. In other words, the history of any one part of the earth, like the life of a soldier, consists of long periods of boredom and short periods of terror.

When I was an undergraduate, I went to the professor of geology and said, “Would you talk to us about the way that continents are drifting?” And he said, “The moment we can demonstrate that continents are moving by a millimetre, I will consider it, but until then it’s sheer moonshine, dear boy.” And within five years of me leaving Cambridge, it was confirmed, and all the problems disappeared—why Australian animals were different—that one thing changed our understanding and made sense of everything.

With such wisdom has nature ordered things in the economy of this world, that the destruction of one continent is not brought about without the renovation of the earth in the production of another.