This image has been chosen for the Edinburgh - Past and Present Exhibition by David McLetchie, MSP - "I was brought up close to Holyrood Park where I played and climbed as a child. We are fortunate to have Arthur's Seat and the imposing Salisbury Crags in the heart of our city" David McLetchie. Salisbury crags were formed by a combination of volcanic activity and glacial erosion. James Hutton's studies of the Crags formed an important part of his 1788 work 'Theory of the Earth', the book that earned him his reputation as the founder of modern geology.