INTRODUCTION, 
3 
'land, swimming in the sea, or flying in the air; to understand 
the meanings of their more obvious structures ; and to form some 
conclusions with regard to their habits, as well as to find out, if 
possible, their relations, — as far as such questions have been 
answered by those most qualified to settle these difficult 
matters. 
All technical details, such as the general reader is unfamiliar 
with, will be as far as possible suppressed. Let us fancy a long 
procession of extinct monsters passing in single file before us, 
and ourselves endeavouring to pick out their “points” as they 
present themselves to the eye of imagination. It is not, be it 
remembered, mere imagination that guides the man of science in 
such matters, for all his conclusions are carefully based on reason ; 
and when conclusions are given, we shall endeavour to show how 
they have been arrived at. 
For millions of years countless multitudes of living animals 
have played their little parts on the earth and passed away, to be 
buried up in the oozy beds of the seas of old time, or entombed 
with the leaves that sank in the waters of primaeval lakes. The 
majority of these perished beyond all recovery, leaving not a 
trace behind ; yet a vast number of fossilised remains have been, 
in various ways, preserved ; sometimes almost as completely 
as if Dame Nature had thoughtfully embalmed them for our 
instruction and delight. 
Down in those old seas and lakes she kept her great museum, 
in order to preserve for us a selection of her treasures. In 
course of time she slowly raised up sea-beds and lake-bottoms to 
make them into dry land. This museum is everywhere around 
us. We have but to enter quarries and railway cuttings, or to 
search in coal-mines, or under cliffs at the seaside, and we can 
consult her records. As the ancient Egyptians built tombs, 
pyramids, and temples, from which we may learn their manner 
of life and partly read their history, so Nature has entombed, not 
one race only, but many races of the children of life. Her 
