The three Appalachian bands by no means preserve a uniform
character throughout their entire length. The eastern crystalline
band has its chief development in the northeast. There it
comprises the whole of New England and a large part of the
maritime provinces of Canada as well as Newfoundland. Its broad
development in New England causes that region to be one of the
most clearly defined natural units of the United States. Ancient
igneous rocks such as granite lie intricately mingled with old
and highly metamorphosed sediments. Since some of the rocks are
hard and others soft and since all have been exposed to extremely
long erosion, the topography of New England consists typically of
irregular masses of rounded hills free from precipices. Here and
there hard masses of unusually resistant rock stand up as
isolated rounded heights, like Mount Katahdin in Maine. They are
known as "monadnocks" from the mountain of that name in southern
New Hampshire. In other places larger and more irregular masses
of hard rock form mountain groups like the White Mountains, the
Green Mountains, and the Berkshires, each of which is merely a
great series of monadnocks.

In the latitude of southern New York the crystalline rocks are
compressed into narrow compass and lose their mountainous
character. They form the irregular hills on which New York City
itself is built and which make the suburbs of Westchester County
along the eastern Hudson so diverse and beautiful. To the
southeast the topography of the old crystalline band becomes
still less pronounced, as may be seen in the rolling, fertile
hills around Philadelphia. Farther south the band divides into
two parts, the mountains proper and the Piedmont plateau. The