CFI AFTER II. 



RANCIE 1;ASE or REFUGE AREAS. 



Results of Climatic Change durintj Post-Tertiary Time — Condition 

 of Europe during; the Ice Age — Condition of tlie Mediterranean 

 Area — North-\\cst Africa during Pliocene and Post-Tertiary 

 Time — The Saharan Region — Influence of the Sahara on the 

 Distribution of Species — North-east Africa— Commingling of 

 Palaoarctic and Ethiopian Types — Homogeneity of the Fauna 

 and Flora of Europe and North-west Africa — Pleistocene Land 

 Connections between Africa and Europe — Effects of Glacial 

 Epoch on the Euro- Asian Mammalia of the Miocene and 

 Pliocene Eras— Commingling of Pala^arctic and Ethiopian 

 Types in the Sahara— Erroneous Views of Naturalists — The 

 Canary Islands — The Cape Verd Islands and the Azores — 

 Range Base or Refuge Area I. — Flora and Fauna — Range 

 Base or Refuge Area II. — Its Climate — Range Base or Refuge 

 Area 111. — Its Uses and Climate — Change of Climate in East 

 Africa — Variations in Climate of Range Base or Refuge Areas 

 — Effects of Changed Climate on Avian Life — The Law of 

 Dispersal — The Southern P^xodus during Pleistocene Time a 

 ^lyth — " Arctic" Animals — The Cape Flora. 



Before proceeding further with our investigations re- 

 specting the dispersal of birds over the British area, it 

 is of the utmost importance to our inquiry that we 

 should endeavour to ascertain the character and amount 

 of that physical and climatic change which took place 

 contemporaneously in areas adjacent to our own. We 

 have already seen that climatic variations during Post- 

 Tertiary time have been enormous and severe. The 



