On the Glaciated Summit of Allei^muir, Pentlaiids. 309 



period, evidence of it might yet exist on the sides or slopes 

 of say the Penthxnds, and it was to search for such that our 

 excursion was projected. This idea, given with all the force 

 of language and aptness of illustration of which Dr CroU 

 was capable, imparted a zest to it which inspirited me to 

 brave the stey braes we had to surmount to verify it. My 

 companion proposed that we should go first of all to the very 

 top of the hills, and if we found them glaciated that would 

 prove at once that the ice had reached that height at least. 

 We therefore set ourselves to climb the two highest peaks of 

 the east end of the Pentlands, called Caerketton and Aller- 

 muir, respectively 1600 and 1618 feet above the level of the 

 sea. We ascended Caerketton first, but found the top a mass 

 of stony d4hris, recently made by the weathering of the rock 

 of which the top consists — a volcanic breccia which frosts 

 could easily split and divide. We looked for glacial strise 

 on some of these fragments, but found none. 



We then descended into the hollow between the two hills, 

 and climbed up to the top of Allermuir. We found the top 

 to be only a few square yards in extent — partly in grass and 

 partly bare rock. We turned to the rock first and saw that 

 it was a hard red porphyrite, quite capable of receiving and 

 retaining striae, and we eagerly looked over the exposed 

 surfaces. At first we found nothing, the surface was too 

 fresh, having been recently formed by fracture from weather- 

 ing. We then examined the fractured pieces lying loosely 

 about, and very soon found some which had unmistakable 

 striae upon one surface. These, we concluded, had formed 

 the original surface of the hill top very recently. Looking 

 round we saw signs that the hill top had been purposely 

 bared — the turf having been taken up to be built round a 

 signal pole for triangulation. Encouraged by this success we 

 then sought the original surface in sitio, and putting the 

 spade into requisition, we soon uncovered a portion, and 

 found it smoothed and as finely striated as it could possibly 

 be. On the very top of the hill was a small space, perhaps a 

 square yard or so, which showed not rock but earth. Into 

 this I struck the spade, and dug till I came at the depth of 

 a foot or so to the rock. The earth I turned up was full of 



