XX. On a Large Boulder of Mica-Schist near Inverbeg, Lochlomond

Abstract

Some years ago, during an ascent of Ben Lomond, we observed a boulder, evidently of considerable size, perched on the shoulder of the hill on the opposite side of the loch, immediately to the north of Inveruglas or Inverbeg.* It stood out in bold relief between us and the western sky; and we mentally took note of the spot where it lay, with the purpose of visiting it at some future time. During last summer we carried this intention into effect, walking from Luss to Tarbet and taking the boulder by the way. As members are aware, the lower part of Lochlomond rests on Calciferous and Old Red sandstones. Its upper part, from above Balmaha on the one side and Rossdhu on the other, extends among the old schistose rocks, provisionally termed Silurian, beginning with a belt of clay-slate, which is wrought for roofing purposes in the well-known quarries near Luss, and succeeded by beds generally of a more arenaceous kind, including varieties of mica-schist, chlorite-schist, etc., such as are common throughout the Western Highlands. The prevailing dip of the whole is to the south-east. The road along the richly wooded shore of the loch, with Ben Lomond rising before us on the opposite side and seen oftentimes through a vista of leafy boughs, presents many aspects of beauty. It belongs, however, more immediately to our subject to state that there are numerous instances of striation observable on the rocks as we walk along, the striae, of course, running parallel This 250-word extract was created in the absence of an abstract