363 
of Edinburgh^ Session 1864 - 65 . 
Lower Boulder -Clay or True Till. 
Per cent. 
White and grey sandstone, 30 
Corstorphine greenstone, . 22 
Common greenstone, . . 12 
Shale of the calciferous sand- 
stone series, . . .12 
Basalt, .... 6 
Quartz pebbles, . . .4 
Cyprid limestone, . . 4 
Per cent. 
Encrinite limestone, . 3 
Ironstone, . . .2 
Felspathic greenstone, . 2 
Greenstone of Mons Hill, 1 
Cement stone, . . 1 
Ash, .... 1 
100 
The list of stones from the lower clay shews with clearness the 
easterly movement of the ice. The most abundant are from rocks 
that occur in situ immediately to the west, and the further re- 
moved the parent mass, the smaller and rarer are the fragments of 
it in the clay. It is to be noted that all the stones are derived 
from rocks that occur in the district ; even those which have come 
furthest need not have travelled more than eight or ten miles. In 
the railway cutting, this lower clay had its upper limit marked off 
by a band of large boulders, chiefly of greenstone, sometimes 
measuring a yard across, and occasionally well striated. The rock 
of Corstorphine Hill was well represented among these boulders, 
and there were likewise blocks of porphyritic felstone and encrinite 
limestone. Above the line of boulders lay an extensive deposit of 
gravel and sand, which, eastward, nearer the Man Trap, gave place 
to an upper sandy clay, in which the stones were found to be more 
rounded than in the lower clay, comparatively seldom striated, and 
to bear evidence of having come from longer distances. In the 
list above given, it will be seen that more than three-fifths of these 
stones come, like those in the till below, from the carboniferous 
rocks of the basin of the Forth ; that sixteen per cent, have tra- 
velled across that basin from the chain of the Ochils, a distance of 
at least five-and-twenty miles, while a still smaller number, nine 
per cent., has been carried from the flanks of the Highland moun- 
tains not less than five-and-forty miles away. Where the upper 
and under clays came together in the section, the band of boulders 
had disappeared, and the two deposits had no very marked line of 
demarcation between. 
Although the sands and gravels of the Kame series have been 
