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The Map That Changed The World
Simon Winchester
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The 1815 map drawn by William Smith marks the beginning of geology as a science. The first step in allowing man to escape religious dogma as an explanation for the world.
Middle Ages familiar with fossils, but interpreted as something God had done. yet why did some rocks have lots of them, and other types none? Robert Hooke one of first to come up with a logical explanation. He identified three stages that were obvious in rocks anyone could examine. in the first stage, wholly unpetrified bones, shells and vegetation found in mud and peat, which were not yet rocks. In the second stage, in lignites and brown coals, more solid but barely rocks, you could see bones and shells and vegetation that had changed, and were half petrified. In the third stage, the layers of soft rock had been turned into coal, and the fossils within had turned completely to mineral as well.
These suggestions anathema to Biblical dogma. Noah's Flood seen as a gentle affair, noy capable of tossing shells up on top of mountains. And observation that some of the fossils were of creatures that no longer existed, challenged idea of perfect creation, with no deaths before Adam and Eve. Yet the fossils were plain to see, and defied conventional explanations.
There are Carboniferous Coal Measures outcropping along the flanks of the Penines in northern England, and in southern Scotland and south Wales. And same era Silesia, Westphalia, France and Belgium, and across vast tracts of Russia. They originate from swampy jungles of tree ferns and mosses. And then, after a few hundred thousand years, the sea swept back in and laid limestone and mudstone on top, pressing down, heating up and compressing the pulp into the hard balck rock we know today as bituminous coal.
In some of those areas (N Eng, Westphalia, Poland) the layers of coal and limestone are undisturbed, and remain flat like a cake. But in south-west England and south Wales the layers have been folded and squashed.
Smith worked in the Mearns Pit, and old colliery in Somerset. The miners taught him what they already knew about how the rocks were laid out in the various shafts that made up the Mearns Pit. Atthe top was a soft red limestone, interspersed with layers of green shales. And the layers sloped gently to the southeast. Then there was an abrupt change to a gray sandstone, the layers of which were folded and shattered, and ponted almost straight down.
At the same time he was trying to imagine how such a set of rocks could have arisen, James Hutton was looking at the rocks of Siccar Point on the Scottish coast. There, thick layers of red sandstone lay flat on top of steeply inclined layers of grey sandstone. Hutton realised that both of these types had been laid down under the sea, but the grey sandstone had been lifted, contorted by some unknown process, and then had the tops of these upended layers eroded and flattened, before sinking below the sea again long enough for the red sanstone to be laid down on top.
Hutton made two impt points. First that these rocks came about by the same processes of erosion and deposition that we could see today. And second, that these processes had occurred over a very very long period of time.
Smith went down many mines, but found exactly same sequence of rocks. And recognizable (by their fossils) seams of coal were always in the same postion to one another. For the first time, he realized that geology was a 3D science.
In first half of C19, increasing numbers of fossils being found as mines, canal and railways excavated. And it became obvious that they were sorted, not randomly distributed. The deeper you dug, the more primitiv ethe fossils. And, crucially, so many were of aorganisms that were no longer to be seen. Slowly, the unthinkable was dawning - concept of God's perfect creation didn't seem to tally with the evidence.
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