Silurian Fossils in the North-west Highlands

Abstract

ON my return to-day from a geological tour in the North-west Highlands, I read with much interest the letters of Mr. Hudleston and Prof. Bonney on the above subject. The question as to the geological position of the limestone series in West Rossshire, correlated by Murchison with the Durness limestone, is one to which I devoted special attention during my late visit to the neighbourhoods of Lochs Carron, Doule, Kishorn, and Maree. The general appearance of the limestone in these areas is sufficiently like that of Durness to lead to the supposition that it is of the same age, but this of course can only be proved by fossil evidence. The conclusion at which I have arrived, however, in regard to the geological position of the limestone, and as to its relation to the so-called Upper Gneiss rocks of the central parts of Ross-shire, is in direct opposition to the views of Murchison, and accords in the main with that of Prof. Nicol. The great triangular patch at the head of Loch Kishorn consists of a series of thick beds of grey limestone, with a few bands of sandstone in an unaltered condition, and is undoubtedly dropped by faults amongst much older strata, as maintained by Prof. Nicol. Between Lochs Carron and Doule the same series is seen to rest unconformably upon much higher beds than those which it is supposed by Murchison and others to underlie at Loch Kishorn. As I purpose shortly to give a full account of these researches, I will not venture now to trespass further on your space.