106 THE OPEN BOOK OF NATURE 
experts. You are sure to find someone who will 
gladly help you. : 
Of course, you won’t spend day after day in 
searching for fossils in igneous rocks! Spend your 
efforts among sandstones, limestones, chalk, shales, 
clays, and gravels. Sometimes you will find among 
gravels and conglomerates fossils that have been 
washed out of clays and other rocks belonging to a 
different Period from that of the rocks you are 
examining. These are called “derived” fossils ; 
don’t be misled by them into wrong conclusions 
respecting their age. 
Your eyes will gradually become practised in 
the art of detecting fossils, and you will learn 
the knack of getting them out of rocks without 
damaging them. A mason’s chisel will help you in 
the latter business, and you must not forget your 
hammer. 
I advise you to make friends with quarrymen. 
They often find fossils and lay them aside. 
When you have got on with your collection, and 
see the interesting results of your work, I am sure 
you will find the gathering of fossils so delightful 
that you will not be content with a merely local 
collection ; you will wish to secure specimens from 
other localities, and to get a collection which repre- 
sents the life of all geological Periods. Holidays 
from home will be utilized in getting fossils which 
cannot be got in your own district, but even if you 
are not able to travel far away from home you can 
exchange specimens with other collectors. They 
say that “ birds of a feather flock together,” and I 
know from my own experience that when a person 
