of Edinhurgh, Session 1883-84. 
843 
axis, these sides would probably meet below j but the excavation 
for the road did not reach that point. The gully had been filled 
with till, and contained numerous boulders, — almost all of which 
were found to be different from any of the rocks on Arthur’s Seat, 
viz., felspar, greenstone, porphyry, limestone (both lacustrine 
and marine), quartz, greywacke, with fragments of shale and 
coal. 
Many of these blocks were found in contact with both sides of 
the gully. The largest blocks were near the north end. The 
large blocks were well rounded ; the small blocks less so. One 
large boulder on the west side of the gully appeared to have been 
pressed against the rock there, and had stuck in that position, 
being rounded and also partially striated on its N.E. side, — 
an indication of the friction it had undergone, by materials 
forced through the gully from a IST.W. direction. 
The gully was not throughout of equal breadth ; at its narrowest 
point, the sides (when the boulder clay and drift were cleared away) 
were found at one place to be about 15 feet nearer one another 
than elsewhere. The rocks on the east side had been ground 
down, smoothed, and striated, some of the striae being continuous 
for nearly 6 feet, and J of an inch deep. 
Generally, the striae were horizontal; but at and near the 
narrowest part of the gully the striae were seen to rise up at an 
angle of 4° or 5°; — caused probably by the obstruction to the 
drift when being forced through the gully. 
One peculiarity in the striations deserves notice, as showing 
the direction from which the striating agent moved. The striae 
were most numerous and deepest on the east side, suggesting that 
the striating agent had moved in a direction from a more westerly 
point than bT.W. The rock surfaces facing the S. and S.W. were 
neither striated nor smoothed. 
There is another spot, on the south side of Arthur’s Seat, worthy 
of notice, on account of the boulders there, and the position occupied 
by them. It is on the west side of Windy Gowl. When the 
new road was being made there, a thick bed of clay and sand, in 
stratified layers, was exposed to view. In this bed, many blocks 
from the overhanging rocks of the hill were found embedded. The 
bed of sand and clay had been formed round these boulders^ showing 
3 K 
VOL. XII. 
