It’s 260 million years before the present day. Off the back of an ice age, temperatures have spiked on Earth, sent soaring by rising carbon dioxide levels. Somewhere on the northern half of Pangaea, Earth’s only continent, a six-legged animal stirs, twitches its antennae, and slinks across a fern-shaded rock to escape the fierce heat of the sun. It lives for a few days, time stretches forward and the picture disintegrates. So, gradually but inevitably, does the continent.
160 million years later: the bristletail’s rock lies submerged in a shallow sea. The water is warm, very saline and populated by a huge range of bivalve and brachiopod molluscs. Many of their shell forms are familiar, such as oysters; others now strange to us will depart along with the dinosaurs at the end of the era. Generation after generation of organisms vanishes into the sediment until this flourishing marine landscape is held within a few centimetres of greensand rock. The sea level falls, and the water above dries up.
The continents clash and part in an imperceptible dance. Rocks rise and fall. The Eurasian plate drifts further north; our rock strata settle into a temperate region. A river valley some way to the south is breached by the sea, filling to become a broad channel. Our patch of earth becomes an island. Wind, water and salt work northward, eating into bedrock which itself once formed the bed of that long-vanished sea. Eventually, piece by piece, this sea floor is revealed again, falling in great boulders out of what is now a sea cliff onto a shingle beach below.
It’s now an unseasonably warm afternoon in late October, and the English Channel is docile. Only gentle waves of remarkably clear water lap at the shingle. Four of us bipedal apes – pretty new on the scene – trace one of the ancient shell beds with our fingertips. A small animal scuttles across the boulder as we marvel at the texture of tangible ghosts in the rock. Six-legged, binocular-eyed, hunchbacked and with three long filaments for a tail: it’s a bristletail, in general body plan unchanged since its ancestor sought shelter beneath a tree fern at the close of the Paleozoic.
It’s almost impossible to conceive of a 260-million-year span. Reframed as a year, let’s say that first bristletail awoke on New Year’s Day. In the first weeks of spring Pangaea breaks up and the continental plates we would recognise today drift apart. The mid-cretaceous warm sea blooms through the summer months before gradually falling beneath layers of soil and rock through September. In mid-October a meteorite falls and the dinosaurs meet their final downfall. A month later, New and Old World monkeys divide. Apes emerge towards the end of November; our earliest recognisable ancestors not until Christmas Eve. Our species, Homo sapiens, arrives just in time for tea (of course) at quarter past five on December 31st. Modern human history fills only the last 20 minutes before midnight.
In a million years or so, this turbulent period in the earth’s history many now dub the Anthropocene will be long buried. Our lives are so brief by comparison we may as well be standing still. The only time available to us is right now, which makes it all the more remarkable that we could spend an afternoon breaking the remnants of eons past out of the rock to hold them between our fingertips, unseen since before the end of the age of dinosaurs. What did we mortal monkeys do to deserve the ability, and knowledge, to hold the life of the ages in our hands and understand something of its vastness?
A fossil Echinoid, possibly a ‘sea potato’.
Greensand with fossils
Possibly looking the wrong way for ancient life…
With some very old rock on Hooken beach near Branscombe in Devon.