50 
REVELATIONS OF GEOLOGY. 
changes in the forms and fashions of organic 
life during each of the long periods he thus 
contemplates. He traces these changes 
backwards through each successive era, till 
he reaches a time when the monuments lose 
all symmetry, and the types of organic life 
are no longer seen. He has then entered 
on the dark age of nature’s history; and he 
closes the old chapter of her records. This 
account has so much of what is exactly true 
that it hardly deserves the name of figura¬ 
tive description.”* 
Sedgwick's Discourse on 
the Studies of the University. 
