A0G6 Murchison’s Siluria. 
The following pages, as before said, will be chiefly devoted to 
the Silurian or first stages of this primeval series. They will be 
illustrated by wood-cuts representing the most important organic 
remains, and certain typical pictorial scenes, as well as vertical 
sections, chiefly taken from my original work. Faithful trans- 
fers from the original plates of the “Silurian System,” will also 
be given, in a rearranged form, and with the modern nomencla- 
ture of the fossils. 
If all the succeeding primeval rocks were to obtain the same 
amount of illustration as the Silurian, this work would be expan- 
ded far beyond the limits to which I must restrict it. The 
younger paleeozoic, or the Devonian, Carboniferous, and Permian 
deposits, will therefore receive only such a description as may be 
sufficient to give the student a general view, and stimulate him 
Although few mineral changes of the strata can be alluded to, 
an endeavor will be made to show, that gold, however it may 
now be spread over the surface, was originally accumulated in 
abundance in the older rocks only especially in those which 
have been much altered), and in the associated eruptive masses. 
stly, it is to be observed, that as the true sequence of the 
oldest fossiliferous strata was first detected in the British Isles, so 
the geological descriptions in this volume will be principally de- 
rived from our insular examples. At the same time, a general 
comparison will be instituted with the contemporaneous rocks of 
different quarters of the globe. 
he importance of having, through patient surveys, mastered 
the obscurities which clouded the history of the earlier periods of 
animal life will thus, it is hoped, be rendered obvious, in showing 
that we have now obtained as correct an insight into the first fos- 
sil-bearing formations as we had previously acquired of the 
younger deposits. 
