Birds, by Dr.
Bowdler Sharpe, and those of Reptiles, Amphibia, and Fishes, by Dr.
Guenther and Dr. Boulenger. The valuable works on Mammalia by Sir W.
Flower, Mr. Lydekker, Mr. Greve, and Dr. Trouessart, were indispensable
to me.

To Sir William Flower, Mr. Lydekker, Professor Sars, and Professor
Smitt, I am especially indebted for allowing me to reproduce drawings
from their works, and to my friend Mr. Welch for some beautiful
photographs. The Council of the Royal Irish Academy also kindly gave me
permission to reprint the maps used in illustration of my paper.
Professor Haddon first suggested my writing this book, and gave me many
useful hints; and great assistance was rendered me by my colleague, Mr.
G. H. Carpenter, in revising the proofs. To both of these kind friends I
desire to acknowledge my deep sense of gratitude.

R. F. SCHARFF.

THE HISTORY OF THE EUROPEAN FAUNA.

CHAPTER I.

INTRODUCTION.

Every student of natural history, whether he be interested in birds,
butterflies, or shells, contributes his share of facts which help to
show how the fauna of his country has originated. The capture of a
Swallow-tail or of a Marbled White Butterfly in England at once
furnishes material for reflection as to the reason of its absence from
Scotland and Ireland. Why should the Nightingale allow its beautiful
song to be heard in England, and never stray across the Channel to the
sister isle or cross the borders of North Britain? Lovers of bird-life
and sportsmen, who have observed the habits of the Ptarmigan in the wild
mountain recesses of Scotland, are aware that nowhere else in the
British Islands do we meet with this interesting member of the grouse
family, and many no doubt have allowed their minds to dwell upon the
causes of its singularly local distribution.

All these animals have a wide range in other parts of the world. In
past times, before man began to make observations on the geographical
distribution of birds and butterflies, or even before the appearance of
man in Northern Europe, they may have lived all over the British
Islands. For some reason or other they are perhaps dying out or
withdrawing towards their original home, which may either be northward,
or to the east or south. If we had some clue as to their former history
from fossil evidence--or, in other words, if their remains had been
preserved to us in geological deposits,--we should have l