]2 ME. T. P. JAMIESON^ — SUPPLEMENTARY 



when it stood across the mouth of Glen Eoy during the time of the 

 two upper lines. Here it made a pause, and that accounts for the 

 presence of such a heap of debris at this particular spot, for the 

 laminated character of part of the materials, and also for the rudely 

 stratified arrangement of the whole. It appears to have filled all 

 the bottom of the glen, reaching near the Gap almost up to the 

 height of the lowest line, but has been cut through afterwards by 

 the retiring water. This mass of debris attracted the attention of 

 -MacCuUoch and other observers; it is particularly noticed also by 

 Prestwich, but so far as I am aware no one has given the foregoing 

 explanation of it. Its existence seems to me to form a most inter- 

 esting link in the chain of evidence for the glacial theory of the 

 lakes, for it is in complete harmony with that theory and with no 

 other. It also shows, in opposition to the opinion of Prestwich, 

 that the lake must have existed for a considerable length of time. 



At the top of Glen Collarig there is a large accumulation of a 

 somewhat similar nature, at the corresponding place where the two 

 upper lines terminate there; in fact the Gap between the hills 

 may be said to be partly filled by it ; and it reaches up to even a 

 greater height there than it does in Glen Eoy, extending above the 

 level of the lowest line. It is also of a more morainic character, with 

 a larger number of boulders, some of them of fairly considerable 

 size and composed of grey granite, others of gneiss containing traces 

 of a greenish material. These stones should be carefully examined 

 in order to trace where they have come from. I found granite 

 boulders also on the hill of Pohuntine up to the very top. 



Prom the fact that the two upper lines come farthest down 

 Glen Eoy on its eastern side, I would infer that the ice-dam was 

 weakest upon that side, and that it gave way there before it did in 

 Glen Collarig. The termination of the middle line on the west side 

 of Glen Collarig is very remarkable : the terrace runs along the 

 side of the hill and stops all at once as if it had been cut away, 

 leaving a projecting mouud truncated at its southern end. 



YI. The Ice-dam at the mouth oe Glen Spean. 



During the last stage of the lake the ice-dam retreated gradually 

 from the entrance of Glen Eoy until it finally stood across the 

 mouth of Glen Spean from Tiendrish to Corrychoille. The glaciers 

 of Glen Treig, Corry Laire, the Larig Leachach, &c., which formerly 

 all came down and helped to swell the mass of ice in the lower 

 part of Glen Spean, now shrank each of them into the mouth of its 

 own ravine. The Corry ISf'Eoin glacier, however, seems to have 

 still protruded some distance out, but eventually the water appears 

 to have come close up to its eastern flank, for the lowest Parallel 

 Eoad is distinctly marked on to Corry Mhaddie, and I thought I 

 could see a small patch of it even on the spur of the hill which 

 separates that ravine from Corry N'Eoin. Here, therefore, we may 

 suppose the lake to have ended, and at its last stage the Corry 

 N'Eoin glacier seems to have gone not very far out, otherwise its right 



