o f Ed i n b in yh, Session 1877-78. 7 0 L 
between these hills is one of denudation. Several hundred feet of 
strata, belonging to the Lower Carboniferous Limestone series, have 
been removed, or scooped out by currents of the ocean. 
“If you examine Sheet 8 of the horizontal section of the 
Geological Survey (by Professor Geikie) you will find on the south 
hill of Campsie the outcrop of the coal and limestone. This sheet 
shows, quite as distinctly as my sketch, the valley running between 
the south and north hills, and the great denudation of the coal 
strata containing the marcasite balls.” 
laoo fi 
Section across Campsie Valley ; coal and limestone strata overlaid by gravel 
and earth. 
These explanations go far to show how the small marcasite ball 
found in the Leith boulder clay probably came from Campsie. A 
geological study of that district indicates the agency of deep-sea 
currents loaded with ice, which flowed upon the Campsie hills from 
the W.hT.W., scooping out the valley which now occurs there, and 
breaking up to a large extent the coal strata in that valley. The 
debris of these strata would be swept along to the eastward; and 
some of the nodules forming part of these strata would be buried in 
the boulder clay now existing at Leith. 
4. The cases which I have just been describing are of boulders, 
large and small, which have come from remote places, now separated 
by an intervening tract of dry land from the present sites of these 
boulders. 
(1.) But there are cases of boulders which to reach their present 
sites must have crossed arms of the sea , even now of considerable 
depth and extent. In such cases, the theory of local glaciers is, 
of course, scarcely conceivable. 
Thus on the Island of Islay, the Committee’s last Report refers to 
several large boulders of rock, differing from any rock known in 
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VOL. IX. 
