Oh the Geoloay of Roxburghshire. 377 



The superficial deposits consist, beginning with the oldest, of the 

 boulder clay, well known in the Lothians, — of sand and gravels, — and 

 of great blocks or rounded fragments of rocks, all strewed over the 

 surface. It was mentioned, that, whilst the boulder clay was depo- 

 sited in tumultuous waters (presenting no signs of stratification), the 

 sands and gravels being for the most part stratified, have been depo- 

 sited by waters not in violent action. The greater number of boul- 

 ders in Liddesdale consist of grey granite, very similar to that of 

 Criff'el, situated between thirty and forty miles to the westward. 



In part 2d, the author observed, that the greywacke formation, 

 presenting as they do enormous foldings, in consequence of which the 

 formation is traversed by ridges and valleys, all running east and 

 west by compass, must have been acted on here, as throughout the 

 rest of this part of the island, by a force or system of forces, which 

 acted in a particular direction ; and that as hardly any igneous rocks 

 whatever occur, within the limits of this formation, it seemed that 

 the greywacke strata had not been elevated and folded together by 

 igneous action, but more probably in consequence of changes in the 

 form of the earth's nucleus, as suggested by Elie de Beaumont. 



The elevation of the greywacke ranges was followed by eruptions 

 of felspathic and a few greenstone rocks, which took place chiefly on 

 the outskirts of that formation ; and from the sediment afforded by 

 the wearing down of these rocks, still at the bottom of a sea, the stra- 

 tified rocks surrounding and partly covering these older rocks were 

 formed. As the heaviest sediment would be deposited first, the sand- 

 stones filled with oxide of iron, and now constituting the principal 

 beds of the old red sandstone formation, would girdle the hills of 

 greywacke and older felspathic rocks ; whilst the strata of white sand- 

 stone, shales, and limestones, being composed of lighter sediment, 

 would be carried farther, and become members of the coal measures 

 situated in Liddesdale, Northumberland, and Berwickshire. 



The formation of the whinstone dykes, one of which was described 

 as running in a NW. direction, for about twenty-four miles, was 

 ascribed by the author to the irruption of igneous matter into fissures 

 previously formed in the earth's crust. 



The beds of gravel and sand, as well as the boulders, the author 

 thought might all be explained on the supposition, that the district 

 had been covered by the waters of the ocean, when they were depo- 

 sited. He adduced facts and arguments for the purpose of shewing 

 that certainly none of these deposits could have been formed by gla- 

 cial action, and that probably submarine currents, or great waves, 

 such as are known to have been produced by submarine eruptions, 

 would be sufficient to account for all the phenomena. 



