GLACIAL PERIOD. 
31 
of the country polished, grooved, and scratched, 
as in the region of existing glaciers, presenting 
an appearance corresponding exactly to that 
described elsewhere, hut we could track the 
path of the boulders where they had come 
down from the hills above and been carried 
from the mouth of each valley far down into 
the plains below. In Scotland and Ireland the 
phenomena were especially interesting. I had 
intended to give in this article some account 
of the “ parallel roads ” of Glen Roy, marking 
the ancient levels of glacier-lakes, so much dis¬ 
cussed in this connection. But the reminis¬ 
cences of old friends, and the many associations 
revived in my mind by recurring to a subject 
which I have long looked upon as a closed 
chapter so far as my own researches are con¬ 
cerned, have constantly led me beyond the 
limits I had prescribed to myself in these 
papers upon glaciers ; and as the story of Glen 
Roy and the phenomena connected with it is 
a long one, I shall reserve it for another 
article. 
