32 



schist), says Humboldt, "is not a trifling phenomenon of lo- 

 cality, but, on the contrary, a phenomenon independent of the 

 direction of secondary chains, their branchings, and the sinuosity 

 of their valleys ; a phenomenon of which the cause has acted, at 

 immense distances, in a uniform manner, for instance in the an- 

 cient continent, between the 43° and 57° of latitude, from Scot- 

 land as far as the confines of Asia." 



Hence it will be observed that the universality of this struc- 

 ture has not escaped attention. 



Dr. M'Culloch, in his description of the Western Islands of 

 Scotland, remarks on the striking uniformity of the beds of 

 gneiss and schist being more or less in a north-east direction. 

 In cutting any of these beds, as they are called, in an east and 

 west direction, i. e. from the eastern to the western coast of 

 Scotland, the lamina would be intersected transversely, and on 

 examination the planes would be found more or less vertical, 

 sometimes leaning to the east and sometimes to the west : any 

 east and west section of considerable length would be found the 

 same. It must be understood, however, that the above remark 

 is confined to the average, because numerous bends and contor- 

 tions of very considerable extent are frequent in this fundamental 

 structure, and are susceptible of constant changes from the effects 

 of chemical action going on in it. 



On the eastern coast, between Waterford and Dublin, the more 

 ancient lamination presents a mean average direction towards 

 the north-east, but is also intersected at various points by a 

 comparatively recent lamination in a north-west direction. It 

 is at these intersections of the old and new lamina that the me- 

 talliferous deposits of Ireland are principally found. In the 

 Barony of Bantry the old laminated structure is much contorted 

 and dislocated. 



In North Wales and the northern part of England similar 

 oblique intersections of the old and new lamina are observed. 

 The most recent lamination of Cornwall is nearly in the direc- 

 tion of the magnetic needle, and corresponding to that of 

 Wicklow. 



The above observations are not founded merely on a super- 

 ficial survey of these districts, but on a laborious investigation 

 under ground, as well as on the surface. Indeed, without studying 



