^28 Geological Society, 



moraines ; also the blocks, large pebbles, and small gravel spread 

 over the first level portions of the valley of the North Esk, after 

 emerging from the Sub- Grampians, to be the residue of moraines 

 re-arranged by water. 



Moraines in Forfarshire. — The cones and ridges of gravel at Cor- 

 tachy and Piersie, near Kirriemuir, and at the confluence of the 

 Carity valley with that of the Proson, are considered by Dr. Buck- 

 land to have been produced by glaciers, and modified in part subse- 

 quently by water. The polish and striae on a porphyritic rock near 

 the summit of the hill, on the left side of the main valley, and im- 

 mediately above the moraines, he is of opinion must also be assigned 

 to glacier action. The vast longitudinal and insulated ridges of 

 gravel, extending for two or three miles up the valley east of Blair 

 Gowrie, and the transverse ban-iers forming a succession of small 

 lakes in the valley of the Lunanbum, to the west of that town, he 

 considers to be moraines; likewise the lofty mounds comprising 

 the ornamental grounds adjacent to Dunkeld Castle ; the detritus 

 covering the left flank of the valley of the Tay, along a great part 

 of the road from Dunkeld to Logierait ; that on the left flank of the 

 Tumel valley from Logierait to Killicrankie ; and on the left flank 

 of the Garrie, from Killicrankie to Blair Athol. 



The vast congeries of gravel and boulders on the shoulder of the 

 mountain, exactly opposite the gorge of the Tumel, Dr. Buckland 

 is of opinion was lodged there by glaciers which descended the late- 

 ral valley of the Tumel from the north side of Schiehallion and the 

 adjacent mountains, and were forced across the valley of the Garry, 

 in the same manner as modern glaciers of the Alps (that of the Val 

 de Bagne, for example,) descend from the transverse, and extend 

 across the longitudinal valleys. Dr. Buckland mentions the mam- 

 millated, polished and striated slate rocks, about one mile above the 

 falls of the Tumel, on the left portal of the gorge of the valley, as 

 the effects of a glacier which descended the gorge : he notices also 

 the rounded outline and polish on veins of quartz, which project 

 eight or ten inches above the weathered surfaces of masses of mica 

 slate near the same locality. Similar mammillated masses of mica 

 slate retaining strise and flutings are visible at Bohaly, one and a 

 half miles east of Tumel Bridge. 



Evidences of Glaciers on Schiehallion. — The north and north-east 

 shoulders of the mountain present rounded, polished, and striated 

 surfaces, many of which have been recently exposed by the construc- 

 tion of new roads. On the left flank of the valley called the Braes 

 of Foss, and near the thirteenth milestone, a newly-exposed porphy- 

 ry dyke, forty feet wide, exhibited a polished surface and striated, 

 parallel to the line of descent which a glacier from Schiehallion would 

 take ; and on the right flank, one hundred yards north of the eleventh 

 milestone, another and smaller dyke of porphyry presented similar 

 phaenomena. In the intermediate space the recently uncovered slate 

 rocks and quartzite are rounded, polished, grooved, and striated, 

 parallel to the direction which a glacier would assume where each 

 surface is situated. 



