IN GLEN TTLT. 361 



junction of the Crochie, and as cut by veins of the red sienite, 

 has in soma parts a stratified structure. Their imperfect cry- 

 stalHsation, the small proportion of the felspar, and their 

 brisker effervescence with acids, are the characters which dis- 

 tinguish them from the sienitic greenstones, that form so con- 

 siderable a part of the northern bank of the valley. Along 

 the foot of this bank, between the Crochie and the junction of 

 the Clochan, angular blocks of sienitic greenstone, with similar 

 varieties, still occur at intervals in great numbers, and shew 

 that the higher parts of the ridge contain a large quantity of 

 this substance. 



137. On the south side of the long straight reach of the ri- 

 ver, granular limestone appears in two or three places. Near 

 the lower end, there are some beds of it extending about sixty 

 yards close upon the edge of the water, in a face of rock that 

 is nearly vertical, and a kw feet in height. The lines, that 

 mark the stratification of the beds, run horizontally in the face 

 of the rock ; but at each end the beds are curved upwards in a 

 remarkable manner, so that at the eastern, the lines of stratifi- 

 cation make an angle of between 30" and 40" with the hori- 

 zon, and at the western, an angle of from 40" to 50°. At the 

 west end, the rock immediately in contact with the limestone 

 is concealed, but the dark-grey aggregate appears within a few 

 yards of it on the brink of the river. At the east end, this ag- 

 gregate lies immediately under the curved extremities of the : 

 beds of limestone. See Fig. iv, in Plate XIX. 



138. On the same side, not a hundred and fifty yai-ds be- 

 low the junction of the Chlochan, and within fifty feet above^ 

 the river, there are beds of limestone, dipping, as usual, into- 

 the face of the declivity, but perhaps rather more to the east-- 

 ward. 



139. At 



