L. A. Necker de Saussure Voyage en Ecosse. 181 



action must hence have proceeded from the north or the south; 

 exerting itself on a vast system of horizontal layers, in a soft 

 or flexible state, this pressure would drive them back on one 

 another, and force them to gain in vertical height what they 

 lost in horizontal extent. Thence would proceed those varied 

 folds which give the most striking idea of a violent convo- 

 lution. Geologists who have ascribed this contortion of the 

 strata to the inequality and irregularity of the substances, have 

 not fairly met the difficulty. Dr. Hutton himself and Pro- 

 fessor Playfair, who described with so much pains these 

 remarkable phenomena, have not given a more satisfactory 

 explanation than those who have combated their doctrines. 

 For, with a little reflection, we can understand that similar 

 effects could have been produced only by a force acting hori- 

 zontally, and in a direction parallel to that of the strata ; and 

 not as they supposed, by an action directed from below up- 

 wards ; a species of force which might no doubt raise the 

 beds in a variety of directions, but could not drive them back 

 on each other in a uniform direction. On approaching the 

 bold promontory of St. Abbs-head, the beds of greywacke 

 are seen to resume by degrees their regularity, and finally 

 become large strata, with plane and parallel surfaces. They 

 are now nearly perpendicular. 



On the banks of the little streamlet, Fasnet, which runs 

 along a valley amid the hills of Lammermuir, there is a rock 

 of granitic aspect among the strata of greywacke. Mr. Necker 

 describes it minutely, and shews that Mr. Playfair was mis- 

 taken in thinking it a genuine granite. It contains more than 

 three elements ; it is a syenitic granite of transition, is found 

 in beds subordinate to the greywacke, and affords an argil- 

 laceous smell when breathed upon. 



On his way from Edinburgh to Arran, Mr. Necker took a 

 cursory view of the scenery of Argyleshire, which sepms to 

 have laid a strong hold on his fancy. " Our eyes," says he, 

 " were rivetted to the savage mountains which surrounded us, 

 to the south and west. These elevations, covered merely^ 

 with a short grass, mingled with a black and melancholy 

 heath, enclosed between them regions more melancholy still. 

 One of them, Glenmolachan, struck us by the extreme soli- 

 tude and profound silence which reigned in it. This sad 

 scene which appears like the valley of death, descends by a 

 rapid declivity between two mountains. A little brook runs 

 in the bottom, and vanishes from time to time among the 

 purple heather. The approach of night, and the dense clouds 

 which obscured the last rays of the sun, added a new horror 

 to this picture. A black lake placed between bleak pro- 

 montories and rugged rocks, without any semblance of human 

 culture or habitation, presented towards the north, a pros- 



