PRESENT OPERATIONS. 
73 
evidence upon more ancient portions of the 
globe^ it will be useful before adverting to 
them, to describe separately such phenom¬ 
ena as may have occurred during the period 
to which secular history relates. 
In our own country we have some opera¬ 
tions now slowly • going on analogous to 
former geological movements. The forma¬ 
tion of peatbogs; the filling up of lakes, 
rivers and estuaries; the scooping out of 
new channels by streams ; gradually alter in 
some places the character of existing vege¬ 
tation, although the relative levels of land 
and water may remain the same. 
The valleys and fens of Britain from 
Caithness to Cornwall, contain the remains 
of forests; and what is worthy of remark, 
the trees are found rooted in situations 
where now sterility reigns. 
In White’s history of Selborne, he states 
that in Walmer forest are many bogs which 
formerly abounded with subterraneous 
trees, of oah, willow, and alder, which the 
cottagers commonly used. He adds that 
one of the peat-cutters had just sent to a 
carpenter in the village the butt-end of a 
G 
