Supposed Fossils from the Southern Highlands

Abstract

IN the article in your last number upon my paper lately read before the Royal Society of Edinburgh, respecting the discovery of some supposed annelid tubes in the quartzites of Loch Fyne, some observations are made on the interest attaching to the question as bearing on the geological horizon of the metamorphic series which constitute the great bulk of the South-Western and Central Highlands. With reference to this question, however, I am anxious to disclaim attaching any great importance to the discovery of annelids, because I do not admit that any real doubt exists as to the Silurian horizon to which our rocks were referred by Murchison. In this country, particularly, the evidence seems to me complete whether fossils be, or be not, found in them; because in this country we have complete stratigraphical evidence from the occurrence of a small local coal-basin in the district of Kintyre. The backbone of that long peninsula consists of the same metamorphic rocks as the rest of the country. Along its shores it is fringed by cakes of Old Red Sandstones which have resisted denudation, or have survived destructive dislocations. At the southern end of the peninsula these sandstones have survived in considerable masses—including beds of conglomerate, of freestone, and of limestones. All these beds rest unconformably on the metamorphic schists and limestones, whilst they are, again, also to be seen dipping and passing under the coalmeasures and Carboniferous limestones in their usual and natural order. There can be no doubt of the order of succession in this case, and it establishes the position of our metamorphosed slates and quartzites as rocks which belong to the horizon below the Old Red.