James Hutton

You can see, conveniently remotely by video, volcanos spitting out molten rock. The rocks harden, age, even wear down if enough time is allowed and flow into the seas, to be deposited as sediment and form new rocks with even more time. Geology has plenty of time, relative to the life span of a human.

But several centuries ago, this explanation was as hotly debated as the magma issuing from these very volcanic vents. One side (the Vulcanists), followed Continental explorers like Desmeret and De Saussere, who thought that all rocks were formed by a molten process, an the other side (the Neptunists), who argued that all rocks were formed under water.

It took a balanced thinker like the Edinburgh-born and educated Hutton, to actually look at the evidence in the field and realise that the truth, as is so often the case, lay between the two camps.

Hutton was educated at Edinburgh University; studying first chemistry, then medicine. Initially he farmed in Norfolk, where he became aware of geology. Returning to Scotland, he made his money from producing Sal ammoniac from coal soot. This income permitted him to further pursue his interest in geology.

In 1767 he returned to Edinburgh, writing scientific papers for the newly established Royal Society of Edinburgh. He began to formulate the theory of a rock cycle, whereby old rocks were destroyed by weathering, and new ones were formed from their sediments.

'..the mountains have been formed by the hollowing out of the valleys, and the valleys have been hollowed out by the attrition of hard materials coming from the mountains.'

To confirm his theory, Hutton and his friend the landscape artist John Clerk, went looking at examples in nature, finding interesting and scientifically valuable examples of unconformities on Arran, at Jedburgh, and at Siccar Point in Berwickshire.

Hutton was eventually recognised as one of the founders of modern geology, and is buried in Greyfriars' Churchyard, Edinburgh.