A journey into the deep past on beautiful Arran

Isolated in the vast Firth of Clyde, Arran is situated just south of the Hebrides and is Scotland's seventh biggest island. Two hours by car and ferry from Glasgow, it has long been popular with holidaymakers from the city.

But it also has another group of fans – geologists, said Stuart Kenny in The Guardian. In few other places than this is the planet's history so clearly recorded on its surface, with rock types "from basically every geological period of the last half-billion years". Observations...