Main image: Maiden Pap (Credit: mark ferguson / Alamy Stock Photo / EEXR5Y)

Definition: a prominent steep-sided hill rising above a plain. From the German, meaning “island mountain”

The Maiden Pap, an inselberg with subdued summit tors developed in Devonian conglomerates

Credit: Alan Moar

The chain of inselbergs in southern Caithness forms some of most striking hill scenery in Scotland, comparable in grandeur, if not scale, to the better known Torridonian Sandstone hills of Assynt. On the clearest days, the cone of Morven is visible across large stretches of the Northern Highlands, from Hoy – and even from south of the Moray Firth.

Isolated hills like these develop in two main ways. Inselbergs of position become isolated by erosion as the slopes of major escarpments retreat – Monument Valley in Utah presents several classic examples. Inselbergs of resistance develop on rocks which weather and erode more slowly than the surrounding rocks. In Scotland, Mormond Hill in Buchan is a fine example, a quartzite residual rising from the surrounding granitic and metamorphic rocks.

The inselbergs of Morven, Smean, and the Maiden Pap are developed in a Devonian conglomerate full of rounded pebbles of quartzite and granite. The conglomerate is firmly cemented by silica and its most resistant masses form tors and lines of cliffs. Although the conglomerate was originally more extensive, the beds forming the Maiden Pap occupy the former core of a syncline. This is  a neat example of topographic inversion – where a down fold has ended up as a hill after deep erosion because the closed fractures in the syncline prevent penetration of water for weathering. The ridge of Scaraben is unequivocally residual, developed in chemically inert quartzite. Like several of the other lower quartzite hills, its slopes are mantled by Devonian breccias which represent consolidated and once deeply buried ancient screes. The summit and northern face of Scaraben lack these breccia covers and the ridge is a product of more recent erosion. Screes formed of enormous blocks of conglomerates mantle the benches and lower slopes. Crampton and Carruthers (1914) provide a full description of  these features.

Godard’s (1965) section of the Maiden Pap, showing the relationship between the Devonian cover rocks and the underlying slopes
Scaraben’s north side

© Copyright Richard Webb / Geograph

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