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liberately introduced the ice to wipe out all previous creatures and leave an empty and bountiful stage
to be occupied by His chosen new race: mankind.
This part of Agassiz's theory tumbled in the 1850s, when fossil finds demonstrated without ques-
tion that most species had survived the ice age, and that the ice couldn't possibly have been global.
Agassiz's many critics had feared the implications of his dramatic white-out, and they were delighted
by this development. Earth was still, after all, a well-mannered and temperate place. Its climate might
oscillate over time, growing a little warmer at times, a little colder at others. But nothing too bad had
really happened, nor anything too extreme.
In the hundred years that followed, several people had noticed the much more ancient ice rocks
of the Precambrian. Geologists had mentioned them in passing. Sir Douglas Mawson, the renowned
Antarctic explorer who knew a thing or two about ice, had spotted signs of them in South Australia,
and knew that they could be seen around the world. “Verily,” he said in an address to the Royal Geolo-
gical Society of Australia in 1948, “glaciations of Precambrian time were probably the most severe of
all in earth history; in fact the world must have experienced its greatest Ice-Age.”
But nobody had run with it. After Agassiz's embarrassment, who would want to declare that ice
could ever have been global? Who'd put forward such an extreme idea, and risk exposing himself to
the inevitable ridicule? Someone, perhaps, who was happy to swim against the tide, who took things at
face value, who was self-reliant, unconcerned about how other people viewed him and made his own
rules about status.
Brian Harland had grown increasingly convinced that the Precambrian was a time of global ice,
one that was vastly more dramatic than the recent puny ice ages. By 1963 he had prepared all his ar-
guments and set off for an international conference in Newcastle, in the northeast of England. He was
ready to put his idea before the world.
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But he had, as it turned out, picked an unfortunate time to
champion the ice rocks. They were about to go crashing out of fashion.
This was largely thanks to the efforts of John Crowell, a geologist at the University of California,
Santa Barbara. John enjoyed going to England. Though he lived in California, he had been seconded
to the Admiralty in London during the Second World War. His background was in geology, but he'd
retrained in meteorology for the war effort. He was one of the three scientists who predicted the height
of the waves, both surf and swell, that would be experienced by troops landing on the Normandy
beaches. Now, on his way to that same conference in Newcastle, he had a paper to present that had
called ice rocks around the world had nothing at all to do with ice.
Through his work in the Admiralty, John had become fascinated by the behaviour of the sea just
beyond the shoreline. In particular, he had started to investigate a set of undersea canyons close to the
California coast. Most geologists assumed that the canyons must have formed on land, and then been
flooded at some point when the sea level rose. But John discovered that the undersea world itself was
a violent place, and that the canyons had been carved out by massive mudslides.
The canyon floors contained a jumbled mess of rocks, sand and stones that had been carried along
on the back of the sliding mud. John realized that this looked just like the supposed leavings from a
glacier. For him, the mixed-up rocks that had been called “glacial” for decades were nothing more or
less than the effect of underwater mudslides. How to explain the ubiquity of these rocks? Simple. You
get mudslides everywhere.
John's idea caught on quickly. He'd written a few papers in the late 1950s, and many researchers
were assimilating his ideas. Trends come and go in geology as in everything else. John's mudslides
were the hot new thing—ice rocks, laughably old-fashioned. When Brian tried to talk about his global
