Sandstone and Sea Stacks
A Beachcomber's Guide to Britain's Coastal Geology

Sandstone and Sea Stacks is a celebration of Britain's coastal geology - ammonites and sand, sea stacks and wavecut platforms. It goes paddling in the rock pools to examine the rock samples so perfectly polished up for us by the sea.

Between the lichen and the low-tide line, everything is out in the open to be looked at: desert sand dunes emerging out of the ocean; cliffs bent and crumpled by two continents crashing into each other; a band of red-hot basalt squeezed from somewhere in Scotland. Britain today lacks glaciers and volcanoes, but the grand geological earth-shifter we do see is the sea, hard at it around our 6000 miles of coast. And as you wander along the edge of the sand, gradually slowing your eye to the beach-holiday speed of looking at things, you see small creatures, seashells and corals from hundreds of millions of years ago.

Real geology isn't looking up the books and memorising long words. Real geology is looking at real rock, and working out what has been happening to it. What Britain is and where it came from, just what's been going on for the last 500 million years: all is revealed, in a continuous slice around our seaside.

Introduction

1 The Sea the Sea

scissors paper stone

ice, the sidekick

2 Understanding Sand

sandstone, siltstone, limestone

pebbles on the beach

fossils

life and times of the ammonite

3 Sediments, Squashed Rocks, Volcanoes

stones with stripes

4 Igneous Antrim

black bottom rocks

5 Folds

mountain excitement

crunch times

6 Faults

stretches of time that are also times of stretch

stones with spots

7 chalk walk

calcite

8 Jurassic Coast: Dorset and Devon

stones that stop

10 The Other Jurassic Coast: Cleveland

Alum money

Whitby: the urine economy

Scarborough rock

11 Red Sandstone Sandwich

12 Coal Coasts

Mountain Limestone meets the sea: Gower Peninsular

13 Greatly controversial Devon

14 Ancient Days

The greywacke grindstone

Pembrokeshire coast

Glossary, Further Reading

Tropical reefs in England: ice in Brazil

My oldest geology book, which dates from 1943, gives a confusing story of Britain. Hot desert conditions prevailed, followed by tropical jungle and coral reefs, followed by more hot desert. For a while we were volcanic, and then a warm sea washed over us, but flip over a dozen pages and crikey, we're in an ice age. Did the world's climate work quite differently in the Long Ago? Or else, was England in an altogether different part of the world? There could be a third possibility, that the World itself flipped over, swapping round poles and equator. That, however, turns out to involve rewriting Standard Grade physics. It takes a truly enormous force to realign a rotating Earth. A passing black hole could do it, but not without breaking the world into bits. It is slightly easier to imagine just the earth's outer layer sliding about, like the skin on an over- ripe peach. The idea that the climate may have been altogether different: that one might be the first choice. The recent (or, strictly speaking, current) ice age happened with England in its present position. So why not, much earlier in our earth, a warm and sunny ‘Nice Age’? The closer you look, the less likely that one becomes. In the Carboniferous Period, tropical coral reefs flourished on the coast of Wales and the Isle of Wight. They flourished at Borron Point, in Dumfriesshire, which is often a chilly spot today. They were also in eastern Canada and – good gracious! – in Greenland. Meanwhile, looking closely at the rest of the world, central Africa and Brazil were suffering an ice age. The man who looked closer was called Alfred Wegener. Wegener was an astronomer and meteorologist – so whenever it was too cloudy to look at the stars, he could just look at the clouds. In his spare time he enjoyed exploring Greenland. But in 1911 he glanced into a geology book that traced the 1500-mile land bridge and the lost continent of Lemuria, and showed how that explained the correspondence of seed-fern fossils in Madagascar and Southern India. And he went, oh come now. Wegener tracked the continents back, matching up the shapes of their shorelines, the fossils found in their ground, the mountain ranges, and the geology. Closing the Atlantic to bring South America next to Africa was just the start. He moved the continents earlier and earlier, through the Cretaceous, the Jurassic, right back to the Carboniferous and the Devonian. He was able to extrapolate, at the start of the Permian Period, a single, huge, continent containing almost all the current land of the entire Earth. The jigsaw matching accounted for the coalfields spread across Britain and North America. It connected together the New Red Sandstone into a single desert, a quarter of the world wide, filling the rainless inland area of that huge continent. During the Carboniferous, Wegener’s moving map not only had England in the tropics, it had South America and Africa passing slowly and with great dignity across the South Pole. Glossopteris indica was an 8m high seed fern that flourished in the Permian period. Along with its close relatives it made up the ‘Glossopteris fauna’ in India: but also in southern America, southern and central Africa. Glossopoterids made up over half the leafy plantlife of Australia, lasting right up until the Great Dying at the start of the Triassic when the whole family got finished off (thus providing a great opportunity for the conifers). That distribution had already called for some long and unlikely land bridges across Atlantic and Indian Ocean when Captain Scott and his party found the first Antarctic Glossopteris beside the Beardmore Glacier. Even with death so obviously ahead, the expedition did not abandon the 16kg of stones that showed fertile forests underneath the ice. They were found on the sledges alongside the bodies of the expedition members. By an odd chance, in 1930 Alfred Wegener was to die in the same way on the Greenland icecap. Perhaps Wegener’s finest contribution was in refraining from offering up any wrong theory as to how continental drift could happen. He simply displayed all the evidence that it had. Even so, the theory didn’t go down with the fossil folk, geophysicists, oceanographers and geologists whose professional toes Wegener had trodden on with the entire weight of the Earth behind him.