EUROPE forms the western part of the great continental land mass of Eurasia, and on physical grounds alone can hardly be considered a separate continent. But its peninsular character and greatly indented coast line, its climate, and above all the political and economic development of the majority of its inhabitants, mark it off from Asia, and justify the usual custom of according it treat ment by itself. In the circumstances, however, it is obvious that the boundary between Europe and Asia must be more or less conventional, and it is generally taken as following the Ural moun tains, the Ural river, and the Manych depression to the north of the Caucasus. The area of the continent as thus defined is about 3,850,000 square miles, or about one-fourteenth of the total land surface of the globe.
Several great physical regions may be distinguished. In the north of Ireland and in the north of Scotland, in Scandinavia and in Finland, are the remains of an ancient Archaean land which has been much worn down, and of which, as the result of extensive fracturing, many parts have sunk beneath the level of the sea. This region, which has been glaciated within recent times, is bordered in places by a peripheral zone of low land, built up in part by the debris brought down by the northern glaciers, and in part by the alluvium deposited by Alpine rivers. To this peri pheral zone belong the Low Countries and the North German Plain.
Further to the south, there lies a great zone of ancient massifs. These include the Central Plateau of France, the Iberian Meseta, and the Bohemian Block, along with fragments of the Armorican Range, which at one time extended from the south of Ireland, through the south-west of England, and through Brittany to the Central Plateau, and such remnants of the ancient Variscan Range as the Ardennes, the Vosges, and the Rhine massif of Germany. Within the barriers formed by these ancient massifs there are great areas in which Secondary and Tertiary rocks have been deposited. Some of these areas are adjacent to the lowlands already mentioned, and along with them form the great European Plain, which extends from eastern England, through France, Belgium, Holland, and Germany into Russia.
In the south of Europe lies the most conspicuous feature in its geography—the great system of folded mountains which includes the Pyrenees, the Alps and the Apennines, the Carpathians, the Balkans, and the Caucasus.
East of the regions already mentioned, and in a sense apart from them, is the Russian massif, consisting of older sedimentary rocks, which lie horizontally, and which have been little affected by those great tectonic movements that influenced so profoundly the geography of the remainder of the continent.
Off the north-west coast of Europe the continentalshelf has'a wide extension, its seaward limit running from the Norwegian coast, by the west of Scotland and Ireland, to the south-east corner of the Bay of Biscay. Within this area the floor of the sea has nowhere a greater depth than one hundred fathoms. In the Mediterranean region, on the other hand, the mountain ranges border a sea whose floor, except in the Adriatic, sinks rapidly to a depth of 1,000 fathoms and more.
CLIMATE.—The climate of Europe is determined mainly by its latitude, and its position on the western side of a great land mass. In winter, the vicinity of the Atlantic coast is warmed by westerly and south-westerly winds from the ocean, and the isotherms run N.N.W. to S.S.E., being turned eastwards in the Mediterranean region, along the northern borders of which they are somewhat closely crowded together. In the interior of the continent the trend is rather N.W. to S.E., but the general rule holds good that temper ature decreases from west to east at this season of the year, except in the Mediterranean region, where the more southerly latitude, the shelter from northerly winds afforded by the mountains, and the modifying influence of the sea, together tend to prevent a marked decrease. In summer the conditions are reversed, the coastal districts, under the influence of oceanic winds, remaining cool, while the interior becomes rapidly heated. In July, the isotherms, outside of the Mediterranean region, run W.S.W. to E.N.E., and temperature thus increases from west to east, in which direction also, as is obvious, there is an increase in the range between the temperature of winter and that of summer.