In the extreme west part of the state these mountains merge, as it were, into a rolling plateau, the Appalachian Plateau, having an average elevation of 2500 ft.
Farther west the serrated crests of the Blue Ridge overlook the Greater Appalachian Valley, here 73 m.
The state is divided into two distinct physiographic provinces; the Alleghany Plateau on the west, comprising perhaps two-thirds of the area of the state, and forming a part of the great Appalachian Plateau Province which extends from New York to Alabama; and the Newer Appalachians or Great Valley Region on the east, being a part of the large province of the same name which extends from Canada to Central Alabama.
The strata here show some traces of the upheaval which formed the Appalachian Mountain chain.
Two of the most productive petroleum fields of the United States are in part in Ohio; the Appalachian field in the E.
In the United States of America the Appalachian mountain system, from Pennsylvania southward, roughly marks the line of the chief coal-producing region.
The Appalachian belt includes, with the ranges enumerated above, the plateaus sloping southward to the Atlantic Ocean in New England, and south-eastward to the border of the coastal plain through the central and southern Atlantic states; and on the north-west, the Allegheny and Cumberland plateaus declining toward the Great Lakes and the interior plains.
- Maryland is crossed from north to south by each of the leading topographical regions of the east section of the United States - the Coastal Plain, the Piedmont Plateau, the Appalachian Mountains, and the Appalachian Plateau - hence its great diversity of surface.
In width, the broad gently-rolling slopes of the Great Cumberland or Hagerstown Valley occupying its eastern and the Appalachian Ridges its western portion.
The Appalachian Ridges of the western portion begin with North Mountain on the east and end with Wills Mountain on the west.
It is least, from 25 to 35 in., in the Greater Appalachian Valley, in the south on the West Shore, and along the Atlantic border.
The Maryland building stone, of which there is an abundance of good quality, consists chiefly of granites, limestones, slate, marble and sandstones, the greater part of which is quarried in the east section of the Piedmont Plateau especially in Cecil county, though some limestones, including those from which hydraulic cement is manufactured, and some sandstones are obtained from the western part of the Piedmont Plateau and the east section of the Appalachian region; the value of stone quarried in the state in 1907 was $1,439,355, of which $1,183,753 was the value of granite, $142,825 that of limestone, $98,918 that of marble, and $13,859 that of sandstone.
The narrow mountain belt is part of the western edge of the Appalachian Mountain Province in which parallel ridges of folded mountains, the Cumberland and the Pine, have crests2000-3000ft.
Trend to crustal deformations which in very early geological time gave a beginning to what later came to be the Appalachian mountain system; but this system had Its climax of deformation so long ago (probably in Permian time) that it has since then been very generally reduced to moderate or low relief, and owes its present altitude either to renewed elevations along the earlier lines or to the survival of the most resistant rocks as residual mountains.
The Appalachian system, originally forest-covered, on the eastern side of the continent, is relatively low and narrow; it is bordered on the south-east and south by an important coastal plain.
The area of the United States may be roughly divided into the Appalachian belt, the Cordilleras and the central plains, as already indicated.
The physiographic description of the Appalachian mountain system offers an especially good opportunity for the application of the genetic method based on structure, process and stage.
This mountain system consists essentially of two belts: one on the south-east, chiefly of ancient and greatly deformed crystalline rocks, the other on the north-west, a heavy series of folded Palaeozoic strata; and with these it will be convenient to associate a third belt, farther north-west, consisting of the same Palaeozoic strata lying essentially horizontal and constituting the Appalachian plateau.
In view of all this it is possible to refer nearly every element of Appalachian form to its appropriate cycle and stage of development.
4364 ft., Killington Peak, 4241 ft.) and their (west) piedmont ridges farther north in Vermont; and in the ridges of northern Maine: these are all in synipathy with Appalachian structure: so also are certain open valleys, as the Berkshire (limestone) Valley in western Massachusetts and the correspondin Rutland (limestone and marble) Valley in western Vermont; an more particularly the long Connecticut Valley from northern New Hampshire across Massachusetts to the sea at the southern border of Connecticut, the populous southern third of which is broadly &roded along a belt of red Triassic sandstones with trap ridges.
Certain extraordinary features were produced when the retreat of the ice sheet had progressed so far as to open an eastward outlet for the marginal lakes along the depression between the northward slope of the Appalachian plateau in west-central New York and the southward slope of the melting ice sheet; for when this eastward outlet came to be lower than the south-westward outlet across the height of land to the Ohio or Mississippi river, the discharge of the marginal lakes was changed from the Mississippi system to the Hudson system.
During the mechanical comminution of the till no vegetation was present to remove the minerals essential to plant growth, as is the case in the soils of normally weathered and dissected peneplains, such as the Appalachian piedmont, where the soils, though not exhausted by the primeval forest cover, are by no means ~so rich as the till sheets of the prairies.
In the same way the western side of the em- Mississippi ~ayment, trending south and south-west, passes along the Emba.vmeni.lower south-eastern side of the dissected Ozark plateau of southern Missouri and northern Arkansas, which in many ways resembles the Appalachian plateau, and along the eastern end of the Massern ranges of the Ouachita mountain system in central Arkansas, which in geological history and topographical form present many analogies with the ridges and valleys of the Appalachians; and as the coastal plain turns westward to Texas it borders the Arbuckle hills in Oklahoma, a small analogue of the crystalline Appalachian belt.
In eastern New York, and almost as much in the southern Appalachian Mountains (Georgia and Alabama); but its average thickness is much less.
Lay east of the site of the Appalachian Mountains throughout the Palaeozoic era, and quantities of sediment from it Were accumulated where these mountains were to arise later.
The thickness of the system varies from point to point, being greatest in the Appalachian Mountains, and much less in the interior.
One member of the middle division of the system (Clinton beds) contains much iron ore, especially in the Appalachian Mountain region.
In many places, but in and near the Appalachian Mountains its thickness is much greatermore than five times as great if the maximum thicknesses of all formations be made the basis of calculation.
The fauna of the Appalachian region is far less like that of Europe, and indicates but slight connection with the fauna of the interior.
Devonian System.The Devonian system appears in some parts of New England, throughout most of the Appalachian region, over much of the eastern interior from New York to the Missouri River, in Oklahoma, and perhaps in Texas.
Like the earlier Palaeozoic systems, the Devonian attains its greatest known thickness in the Appalachian Mountains, where sediments from the lands of pre-Cambrian rock to the east accumulated in quantity.
In the north-west, before descent is made to the lowlands of the stratified belt (St Lawrence-Champlain-Hudson valleys, described later on as part of the Great Appalachian valley), and at the same time the rising uplands are diversified with monadnocks of increasing number and height and by mature valleys cut to greater and greater depths; thus the interior of New England is moderately mountainous.
The Appalachian trends (N.E.S.W.) that are so prominent in the stratified belt of the middle Appalachians, and are fairly well marked in the crystalline belt of New Jersey and Pennsylvania, are prevailingly absent in New England.
The unity and continuity of the district, expressed in the name Appalachian plateau, is seldom recognized in local usage.
The east, where the disturbances of the Appalachian system have developed ridges and valleys of linear trends, which are wanting or but faintly seen elsewhere.
When the two lowlands are traced eastward they become confluent after the Niagara limestone has faded away in central New York, and the single lowland is continued under the name of Mohawk Valley, an east-west longitudinal depression that has been eroded on a belt of relatively weak strata between the resistant crystalline rocks of the Adirondacks on the north and the northern escarpment of the Appalachian plateau (Catskills-Helderbergs) on the south; forming a pathway of great historic and economic importance between the Atlantic seaports and the interior.
The rocks here concerned are the extension of the same stratified Palaeozoic formations already described as occurring~in the Appalachian region and around the Great Lakes.
It appears in the cores of some of the western mountains, in some of the deep canyons of the west, as in the Grand Canyon of the Colorado in northern Arizona, and over considerable areas in northern Wiscpnsin and Minnesota, in New England and the piedmont plateau east of the Appalachian Mountains, and in a few other situations.
Central portion, the White Mountains, a continuation of the Appalachian system, rise very abruptly in several short ranges and in outlying mountain masses from a base level of 700-1500 ft.
Extreme of the natural gas region of the west flank of the Appalachian system; the greatest amount is found in Martincountyin the east, and Breckinridge county in the north-west.
The rugged east section of the state, a part of Appalachian America, is inhabited by a people of marked characteristics, portrayed in the fiction of Miss Murfree (" Charles Egbert Craddock ") and John Fox, Jr. They are nearly all of British - English and Scotch-Irish - descent, with a trace of Huguenot.
The portion of the state lying within the Appalachian Region is commonly known as Western Maryland.