Salisbury Crags, Edinburgh

wee_map_midlandThis locality at the south end of Salisbury Crags, a prominent landmark on Arthur’s Seat and the cityscape of Edinburgh, is of enormous importance on the development of modern geology.

cs_huttonsection

Hutton’s Section on Salisbury Crags, close to Edinburgh city centre © Colin MacFadyen/Scottish Natural Heritage.

Hutton discovered a clear example of the junction between the igneous rock (dolerite) of Salisbury Crags and the underlying sedimentary rock, and used this to illustrate his ideas on how rocks formed by natural processes.  This internationally important locality is often visited by educational parties.

Close to Hutton’s Section, on the path below Salisbury Crags in a disused quarry, stands an isolated outcrop known as ‘Hutton’s Rock’. The rock illustrates a vein of iron ore (haematite) several centimetres thick, that runs through the teschenite rock of the Salisbury Crags sill intrusion. The vein formed as super-heated solutions rich in iron, percolated through fissures in the cooling rock mass.

Hutton's rock, an early example of geoconservation. © Colin MacFadyen/Scottish Natural Heritage.

Hutton’s rock, an early example of geoconservation. © Colin MacFadyen/Scottish Natural Heritage.

The rock is of considerable historical significance, as James Hutton is reputed to have requested that this unusual and interesting geological feature, be saved from quarrying. The site is the earliest known example of geological conservation in the world.

FURTHER reading:

Walking routes and further information about Arthur’s Seat – Geowalks website.
McAdam, A.D. & Clarkson, E.N.K. 1996. Lothian Geology – An Excursion Guide. Scottish Academic Press, Edinburgh.
Lothian and Borders GeoConservation leaflet about James Hutton.