LOWER LAURENTIAN. 
493 
“ the fundamental gneiss,” w^ch is found in the north-west 
of Ross-shire, and in Sutherlandshire (see Fig. 82, p. 112), and 
forms the whole of the adjoining island of Lewis, in the Heb¬ 
rides. It has a strike from north-west to south-east, nearly 
at right angles to the metamorphic strata of the Grampians. 
On this Laurentian gneiss, in parts of the western Highlands, 
the Lower Cambrian and various metamorphic rocks rest 
unconformably. It seems highly probable that this ancient 
gneiss of Scotland may correspond in date with part of the 
great Laurentian group of North America. 
