42 | Great Geologists
Stratal relationships from Elements of Geology, Lyell’s synthesis of the Principles of Geology aimed at a wider audience.
of the first volume. The second volume was based around
refuting Lamarck’s ideas on the transmutation of species. Lyell
was a devout Christian and viewed the presence of mankind
on the planet as exceptional. For ‘Ourang-Outangs to become
men’ could not be possible. He emphasised the inadequacy
of the fossil record and that fossils of modern creatures might
well still be found in ancient rocks. Moreover, animals and
plants that had once inhabited the Earth might do so again in
the future: “The huge iguanodon might reappear in the woods,
the ichthyosaur in the sea, while the pterodactyl might flit again
through umbrageous groves of tree-ferns”. Change on Earth
was constant and gradual, but led in no particular direction.
Nonetheless he was a great believer in the application of fossils
for correlation and the definition of periods of geological time
and subdivided the Tertiary epoch into the Eocene, Miocene
and Pliocene periods based on the relative proportion of modern
species present. He also renamed the traditional Primary,
Secondary and Tertiary periods (now called eras) to Paleozoic,
Mesozoic and Cenozoic, a nomenclature which was gradually
accepted worldwide.
Volume three of the Principles described the composition
of the Earth’s crust and phenomena such as volcanoes and
earthquakes.
Whilst uniformitarianism became a widely accepted doctrine
amongst British and North American geologists in the mid-19th
century it was not accepted by all. Geologists such as Adam
Sedgwick of Cambridge University argued that folded mountain
strata and giant erratic boulders provided good evidence of
episodes of “feverish spasmodic energy” against which modern
processes paled into insignificance. But for Lyell, recourse
to such unobserved events required geology to be based on
unrestrained speculation — the very thing that in his eyes
made the subject unscientific. Better to allow the long reaches
of geological time to let modern processes have a cumulative
effect and thus provide laws by which geological observations
could be interpreted.
Although Lyell and Darwin became friends, Lyell never fully
embraced his friends’ theory of evolution, despite promoting
its presentation in the famous joint paper with Alfred Russell
Wallace in 1858. In 1863, Lyell published The Antiquity of Man
demonstrating the co-existence of humans with now extinct
creatures. When Lyell wrote that it remained a profound mystery
how the huge gulf between man and beast could be bridged,
Darwin wrote “Oh!” in the margin of his copy.
We know today that a combination of uniformitarianism and
catastrophism is needed to explain the rock record, but Lyell