Changes of Level in the Mediterranean area in Meiocene and Pleiocene Ages.--Bone-caves of Southern Europe.--Of Gibraltar.--Of Provence and Mentone.--Of Sicily.--Of Malta.--Range of Pigmy Hippopotamus.--Fossil Mammalia in Algeria.--Living Species common to Europe and Africa.--Evidence of Soundings.--The Glaciers of Lebanon.--Of Anatolia.--Of Atlas.--Glaciers probably produced by elevation above the Sea.--Mediterranean Coast-line comparatively modern. In the preceding chapter we have seen that north-western Europe was elevated, during the pleistocene age, to an extent of at least 600 feet above its present level; so that Ireland was united to Britain, and Britain was joined to the mainland of Europe, proof of this elevation being dependent upon the soundings on one hand, and the distribution of the fossil mammalia on the other. Such a change must necessarily have affected the whole physical conditions of the area, since the substitution of a mass of land for a stretch of sea, and the higher altitude of the land, would tend to produce climatal extremes of considerable severity. It is indeed no wonder that during this time of continental elevation, the hills of Wales, Yorkshire, Derbyshire, Cumbria, and Scotland should be crowned with glaciers, or that there should have been a migration to and fro of animals, comparable to that which is now going on in Siberia and the northern portions of North America. The condition of southern Europe at that time has a most important bearing on any conclusion which may be drawn as to the pleistocene climate in France, Germany, or Britain. For if it be proved that the Mediterranean Sea was then smaller than it is now, the greater land-surface would increase both the heat of the summer and the cold of the winter in central and north-western Europe. _Changes of Level in Mediterranean area in Meiocene and Pleiocene Ages._