On the Geological StrnctuTe of the Highlands of Scotland. 45 



REFERENCE TO PLATES. 



Plate IX. 



Plate IX. Fig. 1. This is a drawing of "The Stack," which, 

 with its neighbours Coul Beg and Coul More, consists 

 of nearly horizontal beds of Cambrian sandstone and 

 conglomerate, resting on a floor of Laiirentian schist 

 and gneiss. The position of this isolated mass is inland 

 from Longh Enard in Cromarty. 



Plate IX. Fig. 2. Represents the grand escarpment of Ben- 

 more Coygeagh, in Cromarty, also consisting of hori- 

 zontal beds of Cambrian sandstone, bi-eaking off in 

 precipices towards the south and west. The rocks 

 of the foreground are of the same formation, and have 

 an eastward dip. The view is taken from the shore 

 of an inlet from Loch Broom, looking north. 



Plate IX. Fig. 3. Represents the great buttress of Cambrian 

 sandstone, in nearly horizontal layers, along which 

 Quenaig ends off towards the north. From the base, 

 the Laurentian floor from which the sandstone beds 

 rise, stretches away northwards and westwards in a 

 rough boulder-strewn tract to theshores of the Atlantic 

 and the dark inlet of Kylesku. The manner in which 

 the lower quartzite of the Silurian series stretches 

 over the denuded edges of the Cambrian sandstones 

 is represented in section, Plate XI., Fig. 9. 



Plate X. 



Plate X. Fig. 4. Ben Stack in Sutherlandshire, seen from 

 the entrance to Loch Inchard. This is a remarkably 

 symmetrical cone of Laurentian hornblende schist, 

 rising 2,364 feet above the Atlantic. The bedding, 

 as also the system of joint planes by which the rock 

 is traversed, are clearly visible, and their relationship 

 to the outline of the cone will be recognised at a glance. 

 The shores of Loch Inchard are composed of the red 

 gneissose beds underlying those of Ben Stack. 



Plate X. Fig. 5. This is a diagram to illustrate the point to 

 which I have drawn attention (p. 11), that at the time 

 the Lower Silurian beds {s. 1) were being deposited 

 in a nearly horizontal position, the Cambrian sand- 

 stone (c.) of the district around Loch Assynt must 

 have had a westerly dip. Upon the upheaval of the 

 former, and on its assuming an easterly dip, the 

 Cambrian beds were placed in their present position 

 of approximate horizontality. 



