The Immeasurable Wilds: Travellers to the Far North of Scotland

Mapping the Landscape: Early Geological maps of Scotland

My interest in the Highlands Controversy has encouraged me to obtain a number of early geological maps of Scotland. I am not a geologist, but I have always thought the wonderful handcoloured cartography of this science is amongst the most attractive available to the map collector.

Books on the full history of geology are few in number, but I can recommend Archibald Geikie's Founders of Geology which was first published in 1905. His study goes back to the ancient Greeks, and he is excellent on Continental as well as British geology. The map that is at the top of this page is by a Frenchman, Philippe Bouache, a Carte Mineralogique, published in 1746 for a memoir by Jean Etienne Guettard. It is the first printed geological map to include the British Isles, and shows that whilst there is plenty of detail in England and beyond, not much was known about Scotland.

Fer, Or, Argent, Plomb, Etaim, Coquilles ou Corps Marins fossiles, and Souffre is marked in the Central Region(Iron, Gold, Silver, Lead, Tin[?], Shell or Fish Fossils, and Sulphur[?]), but only Charbon de Terre and Marbre in the Northern Highlands (Coal, or possibly Charcoal, and marble).

The first printed geological map devoted only to Scotland is no more informative in the far north west:

In the far north, mainly micachiste with patches of gneis, and R. chloiteuses et quartzeuses (quartzite?). 

The map is found at the back of Ami Boue's Essai Geologique su l'Ecosse, the first detailed study of the geology of the country published in 1820, which was dismissed in a review at the time as 'a compound of plagiarism and conjecture', but which Geikie thought ' a most valuable treatise....far in advance of his time.'

Another geological map of Scotland was published 9 years later, this one also giving few deatils. 

This map was the result of a trip to the Far North of Scotland in 1827 by Roderick Murchison and Professor Sedgwick. The purpose of the visit was to explore the Red Sandstone on the east coast of Caithness, and compare it to that on the west coast. They concluded, incorrectly as it turned out, that the two series were of the same age, even though that on the east has fossils, while that on the west has no fossils. So the two sets of sandstone are coloured the same light brown. To be fair, this map was designed specifically to illustrate the findings of their investigation: They state that no further subdivisions were attempted.

John MacCulloch's magnificent map of 1836 is a completely different story, a comprehensive description of the geology known at that time of the whole country. It is a testament to the years of work he endured when investigating not just the easily accessable areas. I do not have an original copy of his map, but the National Library of Scotland display an example on their excellent website. My illustration below is a photograph of the reproduction copy supplied by the Geological Survey.

At around this time, geologists started mapping the individual counties. In 1839, Charles MacLaren published a significant Sketch of the Geology of Fife and the Lothians,  complete with handcoloured sections, a map of the Lower Basin of the Forth, and this fold-out map of the Pentland Hills.

MacClaren acknowledges the work of Robert Hay Cunningham, who had published his own paper on the geology of the Lothians one year earlier, 1838.

In his short life ( he died aged 27), Cunningham managed to survey in detail 6 counties of Scotland.His finest achievement must be his survey of Sutherland, the account of which was published in 1841. Surveying the Lothians was one thing, but travelling up to, and around Sutherland was quite another. As it turned out, the geology of the far north west was particularly interesting, and Cunningham's contribution to the understanding of that geology was of great importance. The map that accompanies his 'Geognostical Account of the County of Sutherland' shows that he had a firm grasp of all the various strata of that region.

Another county to be surveyed at this time was Peebles-shire. which was surveyed by James Nicol in 1843.

Incidentally, geological maps, of course, need to be coloured, and printed colour was still an expensive and complicated option even as late as 1860. All the maps described thus far have been handcoloured, which can today be a problem if the colours have faded.

James Nicol published another handcoloured geological map in his Guide to the Geology of Scotland, 1844. This one was of the whole country.

You can see that he colours the red sandstone of the east coast the same as that found on the west coast. His Geological Map of Scotland, published in 1858, is altogether a different matter. It is much larger, a folding map mounted on linen, using mainly printed colour.

Furthermore, this is the first geological map of Scotland to describe correctly the sandstone of the east coast as younger than that on the west. In notes supplied with the map, Nicol explains that he has taken this decision on the basis of the fossils found at Durness by Charles Peach in 1855, which suggest the sedimentary layers are Silurian in age, which means the sandstone below must be earlier still, Cambrian. It eventually emerged that it is in fact Pre-Cambrian.

Geological maps start to flow thick and fast from this time: Murchison published a 'First Sketch of a Geological Map of the North of Scotland' in 1859, an answer to Nicol's map of a year earlier. Where Nicol has coloured all the rocks that fill much of the Highlands as gneiss, Murchison was determined to describe them as much later, of Silurian age. 

Murchison's map of 1861, which was constructed with the help of Archibald Geikie, makes this point even clearer, with the gneiss of the west coast in violent stripes, while the 'Silurian' rocks of the Central Highlands are in a dull brown.

No way could the two series be confused!

From this time forward, for a period of some 20 years, Murchison carried the 'establishment' with him, their maps reflecting the model that suggested the rocks of much of the Highlands were Silurian in age.

This is the map of Scotland from the first edition of Reynolds's Geological Atlas of Great Britain, c1860. All the maps are handcoloured, making it one of the last such to be published - the second edition appeared with printed colour.

Andrew Ramsay, who replaced Murchison as Director General of the Geological Survey in 1871 was happy to subscribe to the Murchison model throughout the 1870s. He published a huge geological map of Great Britian in 1878. Again, the rocks of the Central Highlands were labelled Lower Silurian, in contrast to the gneiss on the west coast.

Geikie, meanwhile in 1876 had published his own fine Geological Map of Scotland, in which he nailed his flag firmly to the Murchison mast.

One more significant geological map relating to the Highlands Controversy was published before the question of the succession of the rocks of the north west was finally answered was published in 1881. 

Matthew Forster Heddle's Geological and Mineralogical Map of Sutherland was a unique contribution the the debate in that it marked in bright green the areas where the mysterious Logan Rock was found. This was a rock that had been so compressed and heated during the thrust faulting process that no one could make out what it was.

The debate concerning the succession of the rocks of the far north west was finally settles in 1883/4. For nearly 30 years, all the geological maps of Scotland had marked incorrectly as 'Silurian' a large percentage of the rocks of the Highlands.

At this point, the Geological Survey set about investigating in detail this hugely complicated structure. The surveyors were unlucky: the summers of the 1880s were particularly wet, and the terrain and conditions took their toll on the men from the Survey. In 1889 T.M Skae died aged 42, J.R. Dakyns suffered blindness, and H. Miller was ill for most of the year. Previously, in 1887, neither Peach nor Horne did much field work as the former had sciatica, and the latter an 'inflammation.' But by the early 1990s much of the work needed had been done, and the detailed survey maps gradually began to appear. That of Loch Maree was not issued until 1913, and the detail on it gives some idea of the complexity of the job the survey faced in mapping the area.

Inevitably, Archibald Geikie too had to acknowledge the revised assessment of the ages of the various rocks of Sutherland and Ross-shire. This is his Geological Map of 1910.

By this time, the Geological Survey Memoir of the area had been published (1907). The vast area of rocks, marked in pink, stretching down from Sutherland through Ross-shire and Inverness-shire, and on into Perthshire, once the pride of the Murchison Silurian empire, is here marked 'Dalradian gneissose and schistose not yet differentiated.'

At the top, Geikie supplies a section, marking the key thrusts that produced the astonishing landscape that we now enjoy at our leisure.