OP THE MACKINTOSH ESTATE IN BRAE LOCHABER. 235 



of the water draws the loose muddy water down the slopes until 

 the accumulations became too great for the diminishing force of 

 the water to remove, and the debris is left in a sort of terrace. 

 Then a similar process and another terrace is formed. The three 

 terraces alluded to rise to a height of 60, 140, and 200 feet 

 respectively, above the level of the plain that follows the course 

 of the rivers Roy and Spean. The slopes are mostly covered with 

 natural oaks, and while the flats of the first and second terraces con- 

 sist chiefly of arable land portioned out in crofts and small farms, 

 all three are formed almost wholly of clay, sand, and gravel, the 

 proportions varying at different depths and in different parts of 

 the district. For the parallel roads and the phenomena connected 

 with them are not confined to Glenroy, but are more strongly 

 marked there than in any of the other glens. These accumulations 

 often assume the forni of layers, which may be observed at several 

 places, where deep ravines formed by the mountain torrents pre- 

 sent a sectional view of the strata. The surface layer consists of 

 sand and gravel mixed with clay of a loamy nature, and is about 

 3 feet in depth ; the second is a sandy clay to a depth of 40 feet ; 

 the third has only a little clay and sometimes gravel mixed with 

 the sand, and is about 20 feet in depth j and the fourth, which is 

 embedded upon rock, is a bluish granitic gravelly clay, becoming 

 more gravelly toward the base, and is about 8 feet in depth. 



Climate. — This district is bounded on the south by the loftiest 

 mountain range in the British Isles, including Ben Nevis to the 

 south-west, 4406 feet. These high mountains attract the clouds 

 carried from the Atlantic Ocean ; hence the rainfall in the dis- 

 trict is large and the climate generally is very moist and mild. 

 In winter it is milder than in many places further south. The 

 average rainfall during the last three years has been 50 inches, 

 and the days on which no rain fell averaged about 1 in 3. 



I now proceed to describe the trees and plantations. 



Oak (Quercus robur). — This species constitutes the natural woods 

 throughout the district, but is seldom found of a large size ; per- 

 haps this condition may have resulted from successive cropping 

 when young. It grows rapidly till it attains a height of 30 feet, 

 when it begins to assume a spreading form, and its growth is less 

 perceptible. The oak woods grow in a manner similar to larch 

 and Scotch fir plantations, for the trees stand singly, and unless 

 protected no coppice succeeds after the trees are cut down, as the 

 cattle and sheep destroy the shoots and young trees. The trees 



