THE AGE OF THE LAST UPRISE OF THE BRITISH ISLES. 179 



approaches to, or touches, that level above the high-water line. 

 It has been described in more or less detail by several writers ; 

 by Ptobert Chambers in his Ancient Sea-Margins ; by Smith 

 of Jordan Hill ; by Sir Archibald Geikie in the Journal of the 

 Geolorjical Society,^ and more recently in his Scenery and 

 Geology of Scotland.^ I have myself had numerous 

 opportunities of examining this terrace along the western coast 

 and isles as well as in the interior of the country. 



Tlie 25-feet beach forms a fringe along the western coast of 

 Scotland, and is especially conspicuous along the coast of 

 Cantyre and the Firth of Clyde where it affords the most 

 convenient sites for roads, houses and churches. On the one 

 side we have the rocky sea-coast ; on the other the cliff of rock 

 or steeply shelving bank, which formed the old coast-line before 

 the uprising of the land (Fig. 1). On Cantyre the inner cliff is 



FIG. 1. — GENERAL SECTION OF COAST OF CANTYRE. 



A. — Old coast cliff. 



B. — Eaised Beach. 



C. -Cave. 



S. — Sea-stack. 



sometimes perforated by tunnel-shaped caves, the floors of 

 whicli are strewn with rounded pebbles of hard stone which the 

 waves made use of for breaking into the schistose rock. The 

 resemblance to a sea-beach goes still further in the existence of 

 old sea-stacks rising from the surface of the terrace, monuments 

 of wave-action during the uprise of the coast. 



The terrace is likewise well-developed on the eastern coast of 

 Scotland and along the margin of the Firths of Forth and Tay. 

 But physically its most important features are those of the 

 interior parts of this country ; for here it gives rise to the 

 broad plains or " carses," which border the valleys of the Clyde, 

 Forth and Tay, with their branches. To this category belong 



Quart. Journ. Geol. Soc, 1862. 

 t Published 1865. 



