As regards their physical conditions, the original English colonies are divisible into three groups,—those of New England; those of the Chesapeake and Delaware district, including Pennsylvania, Virginia, Maryland, New Jersey, and the central part of North Carolina; and those on the coast region of the Carolinas. Each of these regions has its proper physical characters, which have had special effects upon their early history. In New England we have a shore-line that affords an excellent system of harbors for craft of all sizes, and a sea that abounds in fish. The land has a rugged surface made up of old mountain folds, which have been worn down to their roots by the sea and by the glaciers of many ice periods. There are no extended plains, and where small patches of level land occur, as along the sea, there they are mostly of a rather barren and sandy character. The remainder of the surface is very irregular, and nearly one half of it is either too steep for tillage or consists of exposed rocks. The soil is generally of clay, and was originally covered almost everywhere with closely sown boulders that had to be removed before the plough could do its work. The rivers are mostly small, and from their numerous rapids not navigable to any great distance from the sea, and none of their valleys afford natural ways to the interior of the continent. In general structure this region is an isolated mass separated from the body of the continent by the high ridges of the Green Mountains and the Berkshire Hills, as well as by the deep valley in which lie the Hudson and Lake Champlain. The climate is rigorous, only less so than that of Canada. There are not more than seven months for agricultural labor. The New-England district, including therein what we may term the Acadian Peninsula of North America, or all east of Lake Champlain and the Hudson and south of the St. Lawrence, is more like Northern Europe than any other part of America.