GENERAL GEOGRAPHIC REGULARITIES OF THE EARTH1

Abstract

HYSICAL geography is the study of the distinctive characteristics of the state and development of the landscape envelope of the earth. By landscape envelope is meant the surface of the globe as the scene of complex and reciprocally interacting atmosphere, hydrosphere, and lithosphere, as the surface on which energy from the sun is received and absorbed, as the locale in which the actions of water, wind, and ice take place with the formation of sedimentary rocks, as the plane on which soil is formed, and as the home of plant and animal life. The landscape envelope is an interrelated system with specific combinations of relief, lithic structure, air masses, water vapor, ocean and lake basins, soils, and living organisms. This envelope extends upward as far as the reach of air masses that enter into direct relations with the land or water surface of the globe. Typically it extends downward for only about three miles, the average depth of sedimentary rocks, but in geosynclines to greater depths. Individually and in combinations, features within this relatively thin surface envelope display marked areal variation. Phenomena investigated by physical geography include: (1) the entire landscape envelope as an integral system, studied by general physical geography; (2) separate physical geographic regions or groups of regions or geographic landscapes, studied by regional physical geography; (3) individual elements in the landscape envelope, studied by systematic branches of geography and by related disciplines; and (4) historical physical geography, studied by paleogeography. We are here concerned only with the first of these, general physical geography. As is generally known, each independent science at a certain stage in its development