788 
Proceedings of the Royal Society 
which boulders or “blocs erratiques,” as the French term them, have 
come to their present sites. I allude, not to blocks lying at the foot 
of some mountain crag from which they have fallen, but to blocks 
which have manifestly been transported great distances, after being 
detached from rocks of which they originally formed part. 
That many of the large isolated blocks lying on our mountain sides 
and on our plains have come from a distance, and by some agency of 
tremendous power, is obvious even to an unscientific observer ; and 
the perception of this truth by the popular mind has, in many cases, 
so invested these boulders with superstitious interest, that they have 
received names and suggested legends, which impute the transport of 
them to supernatural agents. 
There are two circumstances which plainly indicate that these 
stones are strangers. 
One is, that many of these blocks are in composition different from 
that of the rocks prevailing in or near the district where the blocks 
are situated, but similar to rocks in distant parts of the country. 
The other is, that some blocks, whilst excessively hard, — so hard that 
it is difficult to break off a portion, are nevertheless round in form — a 
form evidently acquired by enormous friction — such friction as would 
result from being rolled or pushed a long way over a rough surface. 
These round shaped blocks were the first to attract popular 
attention. The name given to them in Scotland of boulders has 
no doubt been suggested by their shape. 
It is accordingly chiefly the rounded boulders which possess the 
traditionary names and legends by which many of them are known. 
Such names as Carlin's Stane , Witch's Stane , Peek or Piet’s Stone , 
Pinged’ s Putting Stone, Giant’s Stone , Clach M’hor , Clachan-an-druid , 
Kirk-Stane , Pedlar’s Stane, Thuggart Stane , and Devil’s Putting 
Stane , are all applicable to rounded blocks. 
When the geologist turned /ms attention to the subject, it was soon 
discovered, that there were many blocks equally entitled to be called 
erratic, not round, but square shaped ; and which, though discovered 
to belong probably to rocks at a great distance, yet showed signs of 
little or no attrition. Moreover, many of these angular or sharp-edged 
blocks were comparatively soft and loose in structure, so that they 
could not have been rolled or pushed for any considerable distance, 
without being broken or crushed. 
O 
