HOLLAND has an area of 12,648 square miles and a population which, in 1911, numbered 6,000,000. Although all the great geological formations are represented in the country nearly 99 per cent. of the whole area is of Quaternary age. About two-fifths of it consists of diluvial lands formed by an intermixture of material carried down from the north by the Scandinavian ice-sheet, and brought from the south—especially from the Rhine massif and the Ardennes—by the Meuse and the Rhine. This region, which includes the east of Friesland and Groningen, practically the whole of Drenthe and Overyssel, the most of Gelderland, the east of Utrecht, and the greater part of North Brabant and Limburg, is a dry, sandy or stony country in which water and bog alternate with stretches of land on which no vegetation can grow. The elevation varies from a few feet above sea-level to over 300 feet in the Veluwe. In the detached part of Limburg in the south-east, older rocks, including the Coal Measures, appear, and in places the land rises to a height of over 1,000 feet.
The remainder of the country is of alluvial origin; much of it lies below sea-level, and, with the exception of the sand dunes along the coast, very little rises more than a few feet above sea-level. Hence, this region, which includes about three-fifths of the total area of Holland, is practically the creation of man, and, if it were not for the dikes which have been built by him, much of it would be liable to submergence by rivers or by the sea. In many places, lakes,
lagoons, and marshes have been drained and formed into polders, and, along the coast, land is also being reclaimed at the expense of the sea. The west of Groningen and Friesland, North and South Holland, Zeeland, and parts of Gelderland, Utrecht, and North Brabant, all fall within this alluvial region.
CLIMATE.—The most important factors controlling the climate of Holland are the proximity of the sea, and the prevalence of the winds which blow from it. The winters, though somewhat colder than in the south-east of England, do not attain the severity of the continental type, and the mean temperature for January is about 35°F. For similar reasons the heat of summer is not very great, and the mean temperature of July is about 66°F. The rainfall is not excessive, owing to the absence of hills, and only in the neigh bourhood of the coast does it exceed 30 inches. On the other hand, the humidity of the atmosphere is high, especially in the west, where the proximity of the sea and the want of natural drainage contribute to this result.