16 Mr Theodore Kjerulf on the Phenomena 
crushed one another, and, fixed in the ice like a diamond in 
a glazier’s cutting-instrument, they have scored the hill side 
with scratches and furrows. 
Over these ‘‘ scouring stones” and sand lie the various 
clays :—Calcareous and marl clays, in such districts as 
presented Silurian limestones and schists to supply detritus 
to the glacier rivers. Above this, shell-clay, wherever the 
height was not too great, or the streams of cold fresh-water 
too powerful to admit of molluscan life. Then follows brick- 
clay without shells, belonging probably to the time when 
the flush of water from the land was at its height. Finally, 
sand and sandy clay above all. 
Stones brought from a distance may be found here and 
there through all these layers ; but most distinctively the 
erratic blocks are found lying stranded on the top of the 
banks. (See fig. 2, p.13). All parties are agreed that ice 
was the agent which brought down these blocks. 
When moraines had been left stretching across the val- 
leys, they would often in the upper reaches become, during 
the time of the glacier’s melting, a dam for an inland lake. 
The floating particles carried along by the river would be 
deposited in such quiet basins, and hence come those inland 
clays which le at heights above that of the marine forma- 
tion. In such lakes, just as in the sea below, ice-floes might 
drift about laden with small and large blocks, which thus 
became erratic. Even in the ice itself, far up in the in- 
terior, large temporary lakes might be formed when the ice 
was melting rapidly ; and there blocks might be drifted on 
floes in a totally different direction from that in which the 
inland ice itself was moving and tracing its furrows. This 
_ may serve to explain how in some places the direction in 
which the erratic blocks have journeyed does not correspond 
with that of the scratchings. 
Such phenomena, then, as we have been considering, could 
not be the work of a flood. A flood strong enough to 
furrow both hard and soft rock, and even to give their 
shape to the mountains, with their weather and lee sides— 
a flood of such incredible force could not have failed to 
sweep away before it all these loose masses of scratched 
stones and debris of sand and mud. Yet here we find them 
