The Scottish Naturalist. 183 



not so rich botanically as those which decompose more readily. 

 Here and there are great masses of Hmestone, which afford an 

 appropriate habitat for some of the Hme-loving plants. In other 

 places the hills are largely composed of granite and other intrusive 

 rocks — as, for example, the great mountain called Ben Dearg (or 

 the red hill), which derives its name from the red granite of 

 which it is composed. 



At Marble Lodge, about four miles up the glen, the limestone 

 is of a fine, hard, crystalline character, white beautifully veined 

 with greenish in colour, and as it takes a good polish, has been 

 used, under the name of Glen Tilt marble, for mantelpieces, &c. 

 Still further up the valley, where Dal-an-eas bridge crosses tlie 

 river, this marble limestone again appears, its veins being inter- 

 mingled with granite and other rocks in a very curious and inter- 

 esting manner. 



The following rambling notes on the zoology and botany of 

 the glen are the combined results of the explorations of several 

 observers, but chiefly of Sir T. Moncreiffe, Mr W. Herd, and 

 myself, though it is by the two first named that most of our know- 

 ledge of the Lepidoptera of the glen — the most interesting portion 

 of its fauna — has been acquired. It may also be as well to state 

 that many of these observations were either made or corroborated 

 during a visit that we paid to Glen Tilt in July last, when, by the 

 kindness of the Duke of Athole, our headquarters were at Forest 

 Lodge, and free permission granted to carry on our explorations. 



Forest Lodge is a shooting-lodge situated about the middle of 

 the glen, and hence admirably adapted as a centre from which to 

 work. The lodge stands on the north bank of the Tilt, on a long 

 narrow piece of natural meadow, from which the hills rise steeply 

 on either side. On the south of the Tilt the hill rises in a very 

 steep green bank for about 600 feet, where it is surmounted by 

 a high limestone rock — Craig Mhbr — above which, again, is one 

 of the tops of Ben-a-Ghlo. On the opposite side of the valley, 

 also, the hill rises steeply for about 600 feet, but instead of the 

 uniform grassy slope of the south side there is considerable vari- 

 ety of vegetation, amongst which the rock-rose {Helianthenuun vtd- 

 gare) holds a conspicuous place. Above 600 feet the slope is less 

 inclined, and heather and blaeberry clothe the surface. Finally, 

 at about 2000 to 2400 feet the summit of the ridge separating 

 Glen Tilt from Glen Cruinnich is reached, which, being followed, 

 leads upwards to a peak about 3000 feet in height. Round about 

 the lodge there is a young plantation of pines and firs, and a few 



