CALTON HILL. 50 



against it 50°, and as the same arrangement is to be observ- 

 ed at Joppa, a village near Portobello, it is evident that 

 the disturbing influences of Arthur's Seat have extended 

 over a considerable area. In the rocks of Arthur's Seat 

 several minerals occur. Calcareous spar abounds, both 

 forming veins and lining cavities ; quartz occurs, either 

 common or amethystine, and is sometimes found penetrat- 

 ed with spiculas of titanium. Jasper is to be met with 

 in several places ; a vein of it occurs near the summit of 

 the hill traversing the basalt, and another is met with in a si- 

 milar position below the old chapel of St Anthony. All of 

 these veins appear to have been produced by infiltration 

 from above ; while chalcedony is frequently to be observed 

 as nodules imbedded in the basalt. 



To the north of Salisbury Crags, in the hill of the Cal- 

 ton,* there is another example of igneous rocks associated 

 with the coal formation ; the form of this hill approaches 

 to the round backed shape, and it rises to the height of S65 

 feet. At the new High School, forming the eminence of the 

 Miller's Knowe, a greenstone occurs of a compact earthy 

 structure. This greenstone is, throughout its whole extent, 

 traversed by contemporaneous veins, which are frequently 

 so abundant, as in numerous places almost to exceed in quan- 

 tity the traversed rock. The minerals which form these 

 veins are calcareous spar and quartz, small crystals of which 

 associated with amethyst line the walls of minute drusy 

 cavities. On the northern side of the hill, and also at the 

 summit, a similar greenstone occurs, differing however in 

 this, that it wants the contemporaneous veins. The struc- 



* The first geognostical account of the Calton Hill, with a section of 

 its structure, was given by Dr Bone' in his " Essai Geologique sur 

 l'Ecosse,'' from the demonstrations and lectures of Professor Jameson. 

 The account here given is from the same source. 



