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Science and Engineering at The University of Edinburgh

School of GeoSciences

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Hutton's Section

Hutton's Section

Locality 5: The locality known as Hutton's Section is perhaps the most famous Geological site in Edinburgh. Here it is evident that a slab of sedimentary rock has been torn away during the injection of the magma that now forms the Salisbury Crags dolerite sill. The remaining broken ends of the strata have rotated upwards as magma tried to force its way along a bedding plane. At the contact the dolerite was originally chilled to a glass, now devitrified. The crystal grain size increases steadily away from the contact. Towards the top of the sill a little way to the south-east there are rafts of sedimentary rock within the dolerite.

Hutton's Section provides conclusive field evidence that the Salisbury Crags sill was formed from a magma that intruded into older layers of sedimentary rock. We now know that the sill is some 25 million years younger! You will be asked to sketch the important features of this locality.

So who was James Hutton?

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