194 Analysis of Scientijic Books. 



masses of the Highlands, or the Grampian hills ; the second, 

 the hills of the southern districts of the Lowlands, or the 

 Lammermuir hills, as also a narrow fringe in the southern 

 limit of the Grampians ; the third fills up the bottom of the 

 large valley or basin laid open between these two mountain 

 masses, and forms the low countries on the shores of Moray 

 Firth, and on the eastern coasts of Sutherland and Caithness. 

 Lastly, the fourth is found every where as a superficial stratum, 

 in the bottom of the valleys, and on all the low grounds of 

 Scotland. The direction from north-east to south-west, which 

 the bands formed by these different districts uniformly affect, 

 is as distinct as may be. It is determined by the general di- 

 rection of the strata, equally from north-east to south-west, a 

 direction which determines also that of the entire chain, and of 

 its different lateral links. Thus the grounds are placed in suc- 

 cession, parallel to the axis of the greatest heights, or to the 

 physical axis of the chain. As to the general inclination of 

 these masses, it must be evidently in a line perpendicular to 

 the general direction, whatever be in other respects the par- 

 tial inclination of the beds and strata which compose them. 

 Now, since the secondary formations rest on the interme- 

 diate, (transition), and these on the primitive, and since the 

 primitive occupy the north-west of the country, whilst the 

 passage of the oldest regions into the newest, takes place in 

 advancing from that point to the south-east, we may thence 

 conclude that the general inclination of each district is towards 

 the south-east. Thus we shall represent the great classes of 

 formations, as forming each an immense mass, or bed, running 

 from south-west to north-east, and dipping towards the south- 

 east. From this position, however, we must except the class 

 of secondary formations, because here at least it has been 

 manifestly deposited in a basin ; and, although it participates 

 on the borders of the basin, in the general direction, it has not 

 any determinate single inclination, because it rises up on every 

 side, at these borders. 



The 'primitive formations occupy all the space included be- 

 tween the Pentland Firth, which separates the Orkneys from 

 Scotland, and the southern limit of the Grampians, with the 

 exception of a secondary band on the coasts of Caithness and 

 the Moray Firth. Three principal formations, or three very 

 distinct masses, occupy this space ; these are gneiss, mica- 

 schist, and schistous chlorite which here holds the place, and re- 

 presents the formation of clay-slate. The topographical limits 

 between these three formations cannot be fixed with perfect 

 precision, because there is a gradual transition among them. 

 Yet we may say that the longitudinal valley of the Caledonian 

 canal presents pretty nearly the limit between the formation of 

 gneiss and of mica-schists, the former predominating in the 



