THE GEOLOGIST. 
NOVEMBER, 1859. 
THE COMMON FOSSILS OF THE BRITISH ROCKS. 
By S. J. Mackik, F.G.S., F.S.A. 
(Gontinued from page 388.) 
Chap. 6. — First Traces of the Succession of Life. — The Lower Silurian 
RocTcs. 
As ONE carried beyond his depth for the first time into the waters 
of ocean, and struggling shorewards, touches but now and then the 
yellow sands, with every heaving wave again to be set afloat, feels a 
delight when he plants his foot solidly on the sands, and wades 
through shallower water to the shore, so do we after oui* almost 
footless path through the wide waste of water of the first age, hail 
with delight our firmer footing on the spreading shores of this next 
great geological period. 
The first argument of the antiquity of the globe is drawn from the 
successive accumulations of strata inclosing different creations of or- 
ganic beings, which form the stratified portion of the earth's crust. 
The next argument of length of time is taken from the evidence 
which the remains of those ancient organic beings afford of the 
long periods of their existence on the face of our earth. It is not 
the strange obscure forms of three-lobed legless crustaceans, revealed 
to us by such distorted and crumpled fragments that the eye is 
strained in the efibrt to make out the details of their shapes, that 
astonishes us so much as the familiar look of the little shell-fish we 
meet in these old Silurian rocks. 
VOL. II. 0 0 
