Many of the most characteristic animals of the dry modern plateaus of Africa had disappeared from Europe before the close of Pliocene times, namely, species of gazelles, antelopes, and the hipparion horses, all of which were adapted to the dry uplands or deserts of Africa. In the remaining _faune Pliocène récente_ of French authors we find evidence that the Pliocene in all of western Europe closed with a moist, warm, temperate climate, with wide-spread forests and rivers interspersed with meadows favorable to the life of a great variety of browsing deer as well as of grazing elephants, horses and cattle. The flora of the Middle Pliocene as found at Meximieux indicates a mean annual temperature of 62° to 63° Fahr. One of the proofs of the gradual lowering of temperature toward the close of Pliocene times in Europe is the southward retreat and disappearance of the apes and monkeys; the Upper Miocene gibbon is found as far north as Eppelsheim, near Worms, Germany; in Lower Pliocene times the monkeys and apes are found only in the forests of the south of France; in Upper Pliocene times they are recorded only in the forests of northern Italy; the evidence, so far as it goes, indicates a gradual retreat toward the south. Finally, at the end of the Pliocene there existed very close geographic relations eastward with the mammalian life of India by way of what was then the isthmus of the Dardanelles and southward with the mammalian life of Africa by way of the Sicilian land bridge. This would indicate that the long lines of _eastward_ and _westward_ migration were open and favorable to the arrival in western Europe of new migrants from the far east, including perhaps the most primitive races of man. _There is not the least evidence that Pliocene man or ancestors of man existed in Europe_, excepting such as may be afforded by the problematic eoliths, or most primitive flints. THE FIRST GLACIATION In Upper Pliocene times cold marine currents(6) from the north began to flow along the southeastern coast of England, with indications of a gradually lowering temperature culminating at a time when the sea abounded in the arctic mollusks, which have been preserved in the 'Weybourn Crags,' a geologic formation along the coast of Norfolk. This arctic current was the herald of the First Glacial Stage.