On Tuesday 21st March at Stratherrick Hall, we were treated to a fascinating and sometimes mind-boggling illustrated talk by Sandy Ross, retired Head of Geography at Millburn Academy, Inverness. Anyone who knows Sandy is very aware of his huge enthusiasm for his subject, which came over so clearly as he graphically described the effects of the Wurm glaciation – the most recent stage of the Ice Age – on the land that the Inverness area now occupies. Ice two or three kilometres thick covered the Highlands, and was slowly grinding over the land as gravity caused it to move down towards the sea – which it also covered. The rocks in the Loch Ness area had been shattered by earthquakes along the Great Glen Fault (much more active in the distant past), so the huge weight of moving ice easily gouged out this loose material to form the trough of the Great Glen.
Nearer Inverness, streams flowing under the ice deposited this material to create eskers, in the form of Torvean and Tomnahurich, and ‘marine platforms’ where the deposited material met the sea. Once the ice all melted after the Ice Age, the land slowly rose up due to the release of the ice’s weight (this ‘isostatic’ readjustment is still going on), so the marine platforms are now high and dry, and the steep edges of them form the slopes climbed by the likes of Godsman’s Brae and the Market Brae Steps. Much of the finest material carried by water under the ice ended up in what is now the Beauly Firth, explaining why it is so shallow, silted up by all this deposition.
Sadly for an enthusiast like Sandy, man’s constant ‘development’ of Inverness’s site with ever more powerful earth-moving machinery means that the evidence of the work of these amazing natural forces thousands of years ago is becoming increasingly difficult to trace. It is just as well that it is being recorded, mapped and photographed by the likes of Sandy, before it becomes further blurred by man’s activities.
Bob Main proposed a well deserved vote of thanks to Sandy, who answered many questions from a good-sized audience, while Alison Randall and Heather Macleod ably served tea, coffee and biscuits to all.
N.B. Sandy’s talk was preceded by a brief AGM of the Wade Bridge of Whitebridge Trust, chaired by John Townshend. John reported that essentially nothing had changed over the last year. The bridge is stabilised and safe, but awaits further funding to complete its restoration.