The Atlantic border of North America is abundantly supplied with fine harbours, which not only favour communication with distant countries, but are within easy reach of agricultural and forest lands and important coal and other mineral deposits adjacent to the coast or in the interior, and are near extensive and valuable fishing grounds. The best of these harbours are at the mouths of rivers which have been depressed so as to form estuaries with wide entrances. These sea-gates, however, are frequently contracted, owing to the presence of sand-bars and spits deposited by shore currents. The great St. Lawrence estuary reaches to Montreal, and beyond lie the Great Lakes, the rich lands of Ontario and New York, and the now highly productive States of the Middle West. Two geographical features in this basin detract from the conditions otherwise highly favourable to commercial development, namely: the rapids in the St. Lawrence between Montreal and Lake Ontario and the fall in the Niagara, and the winter climate of Canada, which causes the rivers and estuaries to be ice-bound for a considerable part of each year. To obviate the first of these unfavourable conditions far-reaching plans for a deep waterway between the Great Lakes and the Atlantic are now being matured. The splendid harbours from Nova Scotia southward are never seriously obstructed by ice, and south of Virginia ice is practically unknown. The estuaries at the mouth of the Hudson, Delaware, Susquehanna, Potomac, James, and the Alabama, together with the distributaries of the Mississippi (which is not a partially drowned river, but one that is building up and extending its channel), are the natural outlets of portions of the continent of great fruitfulness. When other, and especially climatic, conditions are considered, it will be seen that to the geographer the Atlantic sea-border from the Gulf of St. Lawrence to the Gulf of Mexico seems destined to be the next great commercial centre in the succession from Greece to Britain. An important adjunct to the present highly favourable geographical conditions pointing to a great future for civilization on the Atlantic coast is the construction of a ship-canal across the isthmus uniting North and South America. This step must soon be taken.