122 Ol"l UNI s oi i n LD-GBOD PARTI 



Some <>f these primeval mountains lluis 

 .iletl are more than 3000 feet hi^h. 

 In collecting evidence on the subject of a supposed 

 unconformability tli< r should endeavour to realise- 



to himself what must have been the contour of the 

 ground at the time when the overlying rocks 



FIG. 31. View of Quinaig, Sutherland. The Archaean fjnciss mes in t: 



hand part of the mountain into a. hill some 700 feet high, which is capped 

 and still partially surrounded by nearly flat sandstone and conglomn 



accumulated He may in this way sometimes be led to 

 see that his suspected unconformability is extremely un- 

 likely, or physically impossible. As a curious illustration 

 of the consequences of the want of this precaution 

 Fig. 32 is here inserted from a published geological 

 section. The horizontal distance represented is about 

 six miles, and as the upper rocks are made to dip at 

 angles of between 40 and 50, there must be a mass of 

 them somewhere about four and a half miles thick. If 



