The Rocks Remain –
But Rarely Unmoved
Scourie and District
Classic crofting landscape with raised beach amongst cnoc and lochan terrain and the Scourie ‘dykes’.
Durness Limestone
Durness has a band of rock running through the parish which produces very fertile soils and unusual plants for this latitude. This is of course the Durness Limestone where rare plants like mountain avens and globe flower are found. Balnakeil is a good place to see the rich plant life which thrives as a result of the limestone. Limestone weathers in a very particular way which creates cave systems like the famous Cave of Smoo. A smaller area of limestone is also found on the east shore of Loch Erribol. That’s the area where people were cleared from of course, since the grazing on that kind of ground is exceptional. It is well know that the western shore – and the township of Laide – has none of that rich limestone grazing. It is on quartzite and is a very hard place to raise a crop.
Dykes and Plugs
Among the Moine rocks which cover Tongue and Farr are also to be found dykes, formed by igneous material. As the name ‘dyke’ suggests these are thin bands of molten rock which were forced into fissures and later cooled. The igneous rock is very hard and so resists erosion. Scourie also has significant dykes, visible on the shoreline.
Volcanic plugs are similar to dykes but instead of the molten material flowing along long, thin fissures which are later exposed by erosion, the igneous material flows upwards to ‘plug’ a particular vent. On the borders of Mackay Country Ben Griam More is an example. The area around Ben Griam Mor and Beag is made of Old Red Sandstones, the rock type which is most prevalent in Caithness and the Orkneys. Eilean nan Ron is made of the same type of rock.[1]
Much larger flows of igneous material created the granites of Strath Halladale and the syenites of the Loch Loyal area. The difference that geology makes can be seen in the stark contrast of the rolling and fertile Halladale landscape when compared to the cnoc and lochan dominated Fiondle and Fanagmore in Eddrachilles. Sheets – or narrow bands - of Granite are also found running down Strath Stack and out to sea at Laxford.
Strathy Point – Metamorphic Rock
A headland of granitoid. To the east of the Point is the Balligill outlier of Caithness flagstone. The headland is rich in plant life, including the Scottish Primrose.