In this great Old-World continent there are many highly individualized areas, each separated from the rest of the continent by strong geographical barriers; it has a dozen or so of great peninsulas upon its seaboard, many great islands off its shores, and the interior of the land is divided into many separated regions by mountain ridges or by deserts. It is a land where man necessarily fell into variety, because of the isolation that the geography gave. If we look at the other continents,—namely, the Americas, Africa, and Australia,—we find that they want this varied and detailed structure. They each consist of a great triangular mass, with scanty subordinate divisions. In all of them put together there are not so many great peninsulas as there are in Europe. If we exclude those that are within the Arctic Circle, there are but few on the four regular continents, none of which compare in size or usefulness to man with the greater peninsulas of the Old World. The only one of value is that of Nova Scotia, in North America. These regular continents are all in the form of triangles, with their apices pointing towards the southern pole. Near either long shore lie the principal mountain systems that give definition to the coast line. The middle portion of each continent is generally a region of plain, somewhat diversified by lesser mountain systems. Along either shore is a narrow fringe of plain land to the east and west of the main mountain chains. Near the northern part of the continent, and aiding to define the base of the triangle, there is another system of mountains having a general east and west course. With the exception of North America, none of these regular continents have seas inclosed within their areas,—such bodies of water as form so striking a feature in the Asiatic continent, which is indeed a land of mediterranean seas. In a word, these continents are characteristically as simple as the Asiatic continent is varied. Their mass is undivided, and their organic or human histories are necessarily less diversified than in such a land-mass as Asia. The continent of North America is, of all the triangular continents, the most nearly akin in its structure to the great Old-World land. In the first place, it is the only one of these continents that has the same general conditions of climate; then it has a far greater diversity of form than the similar masses of South America, Africa, and Australia. North America has several considerable seas inclosed within its limits or bordering upon its shores; its mountain systems are more varied in their disposition than in the other regular continents. So that in a way this continent in its structure lies intermediate between the Asiatic type and what is considered the normal form of continents.