The Stirling Dolerite

Abstract

A glance at the Geological Map of Scotland will show that Stirling Castle stands on one end of a very large mass of intrusive igneous rock. Its continuity has been broken by a long east-and-west fault a little south of St. Ninian's, but if we ignore this break the mass of igneous rock has a length of about 8 miles and a width varying from about ¼ to nearly 2 miles. The rock has been intruded into strata of the lower part of the Carboniferous Limestone Series, and it forms not one, but a number of irregularly-shaped intrusive masses or group of sills, all more or less connected with one another. The hardness of the igneous rock has in many places been sufficient to arrest denudation, and the result is a number of crags, which often resemble Salisbury Craigs, near Edinburgh. Sometimes these crags face the north or north-west, as in the case of Stirling Castle and King's Park, but in other cases they face in a different direction, at Sauchieburn, for instance, the north-east. As I shall show from the character of the rock, we can have little doubt that the mass of the Abbey Craig north of the river Forth is connected underground with the Stirling Castle rock, from which it is only divided by alluvium, and there is reason to think that the igneous rocks of Cowden ]~ill and of the hills around Kilsyth are also outlying portions of the Stirling rock. It is not meant that