580 Proceedings of the Royal Society 
Specimens of these boulders, found by me in Cantyre, I sub- 
mitted to Professor Heddle of St Andrews University, so well 
known for his acquaintance with the igneous rocks of Scotland, and 
their mineralogical composition. He has kindly supplied the 
following notes : — 
(1) Most of the Southend boulders, and those along the east 
coast between Campbelton and Southend, are identical in composi- 
tion with one variety of the coarse porphyritic rock of Davar 
Island, situated at the mouth of Campbelton Bay. 
(2) One specimen is a small-grained white granite, which I think 
I have seen somewhere in Arran. 
(3) One specimen from the west coast is a coarse grey granite, 
identical in appearance with the granite of the Mourne Mountains 
in the N.E. of Ireland. I observe in this specimen two crystals of 
topaz. This granite, from containing also crystals of albite and of 
a lithian mica, should be easily recognised. 
2. Loch Lomond . — On the west side of the lake, near Arden, 
a lateral valley runs up towards the west. There is a horizontal 
terrace in this valley about 70 feet above the lake, bounded by 
a steep bank, showing that at one time the lake had filled the 
valley up to that height. On this flat lie a number of quartz, 
granite, and mica schist boulders, which most probably all came 
from the westward, as the rocks in the valley are Old Bed Sand- 
stone. The head of the valley reaches to about 150 feet above 
the sea. The land then slopes down westward towards the sea in 
Loch Long. If these boulders were floated from the westward, it 
must have been when the sea was at a greatly higher level than 150 
feet. The largest of these boulders, a mica schist, I found to be 
5x3x3 feet, with its longer axis lying E. and W., and its sharpest 
end towards the west. 
On the east bank of the loch, nearly opposite to Arden, on the 
farm of Over Balloch, and at a height of about 337 feet above the 
sea, I found a grey granite boulder, 5x4x4 feet, much rounded. 
Its longer axis lay in like manner E. and W. It was on a bed of 
boulder-clay. It most probably had come from the west or north- 
west, crossing therefore the valley now occupied by Loch Lomond. 
3. Loch Long and Gareloch . — On the ridge between Gareloch and 
Loch Long I found several boulders. At a height of 160 feet above 
