The Scottish Naturalist. 319 



then the higher haugh began to be constructed out of the 

 glacial debris, just as the lower haugh is now being constructed out 

 of the higher. We have but to see the bed of the river on a 

 level with the top of the red and blue clay band deposits — that 

 is, some twenty feet or more higher than the bottom of the pre- 

 sent stream, and there can be no difficulty in believing that the 

 higher and lower haughs both are re-arranged glacial deposits 

 sifted and sorted over and over again through the long, long 

 years, by the waters that come down the valley. The pebble 

 beds are the well rolled fragments of what were massive angular, 

 scooped, and scarred pieces, such as now abound on either 

 side of the valley, in the boulder clay of the higher reaches. 

 The examination of the present river of the lower and the 

 higher haughs testifies to the truth that the comparatively 

 little stream, the Earn, has wrought a great work since it 

 became a river, and is Still carrying that great work on. I 

 must, however, be brief. In the higher haugh, there is a fine 

 clay at the top, passing downwards through stratified silt into 

 sand and pebbles, and finally into positive pebble-banks. The 

 lower haugh consists of fine clayey soil (coarser than that 

 above, from constant washing), which passes down through 

 stratified silt and gravel, which merges into vast pebble-beds. 

 In the higher haugh is the remains of a once extensive forest. 

 The trees, I am persuaded, are not mere drifted trunks, but 

 grew and fell where they are lying. Such a forest would readily 

 spring up upon the sand-bed upon which they occur ; but I do 

 not think the peat layer was formed by the trees. I presume 

 to think it more probable that some climatic change, or some 

 alteration in the general level, induced a growth of moss, when 

 the trees, dying, fell down gradually where they stood, and were 

 enveloped in the moss. Possibly the two conditions may have 

 existed in the valley together, but never in the same spot at one 

 time. I have seen the embedded trunks without the peat, and 

 the peat without the trees, and the two together. I was very 

 pleased to see in a clay pit at the foot of Fechney School, just 

 outside Perth, what I doubt not is a continuation of, or rather 

 a sequel to, the higher haugh in the Earn valley. . There was 

 the same clay and the same vegetable zone uncovered. One 

 large trunk lay down, just as trees often fall, with its head much 

 lower than its rooted end. Another had broken off short, so 

 that its base stood upright in the clay. Below this, I doubt 

 not, the sand-bed might be reached. A portion of a tree in 



