168 Geological Observations made in Scotland, 



of our crystalline-slate central masses ; but on this subject 

 it is unnecessary to say more than a few words. Mont Gott- 

 hard, the Bernese Alps, and Mont Blanc, are certainly not 

 the still remaining centerings of former arches, which, if 

 they had existed, must have extended over the entire space 

 now covered with mountains of limestone and sandstone. 

 Still, however, we may anticipate, from the farther investi- 

 gation of these phenomena in England, much that would 

 have an important bearing on the geology of the Alps ; and, 

 since the great Geological Survey of England, under the 

 charge of De La Beche, is just at the present time proceed- 

 ing in^Wales, the desired results will ere long be laid before 

 the public. On the fan -like structure of the central masses 

 in the Alps, as well as on many other matters connected 

 with those mountains, we shall obtain a clear light, only 

 when similar phenomena shall have been deciphered in re- 

 gions presenting greater facilities for investigation. 



In Scotland, my attention was, as may be supposed, par- 

 ticularly directed to the phenomena of the course and contact 

 of eruptive rocks; and, under the skilful guidance of my 

 friend Forbes, I saw, in a comparatively short time, most of 

 the classic grounds on which modern science has fought out 

 its most brilliant victories. What a multitude of important 

 facts is afforded by the ground on which Edinburgh is built, 

 and the country in its immediate vicinity ; and how fully and 

 variously is the inquirer instructed by men such as Jameson 

 and Maclaren ! In the Highlands of Perthshire we visited 

 Glen Bruar and Glen Tilt, where, for the first time, Hutton 

 discovered the penetration of granite veins into the superin- 

 cumbent rock. The white marble, with serpentine veins, 

 which appea ". lower down the river Tilt, and is an al- 

 tered condition of the dark-grey limestone of that locality, 

 reminded me vividly of Predazzo. Both places bear witness 

 to the metamorphic origin of serpentine ; and also in Wallis 

 (Valais) and rPiemont (Piedmont), where the serpentine in 

 gneiss and mica-slate hills forms greater masses, it is usually 

 found in close connexion with limestone and dolomite. Gra- 

 nites and porphyries rise up on a larger scale in the wild 

 Glencoe, which leads from Kingshouse to Balahulish. Here, 



