-THE GREAT VALLEY 273. A great valley highway.—The Great Appalachian Valley is a very long one, fur nishing a continuous open road north and south through the eastern highlands. It is a king of natural highways. One may travel over its entire length, from the Hud son Valley to the Cotton Belt, and not cross a single mountain ridge. All the way one may see to the east and to the west, mountains which run parallel to the Great Valley but never cross it. Look at Figs.15 and 21, and see the towns that mark its course—Bir mingham, Chattanooga, Knoxville, Bristol, Roanoke, Staunton, Hagerstown, Harris burg, Reading, Bethlehem. What river drains the land where each of these cities stands? At Birmingham, Alabama, the open valley extends for some distance into the Cotton Belt.
The Great Valley has long been a route of travel. Even in the days before the Revolu tionary War, its open surface tempted the English Quakers and the German colonists of eastern Pennsylvania, who traveled and settled in this valley all the way down to the headwaters of the James.
Later this route helped other settlers on their way to the valley of the Ohio. Some left the Great Valley near Shippensburg in southern Pennsylvania, and went over the mountains to Pittsburgh. From this point flatboats drifting down the Ohio River took settlers to points in Ohio, Indiana, and Ken tucky. Other settlers from Maryland, Vir ginia, and North Carolina, bound for Ken tucky, drove on down the Great Valley to the headwaters of the Tennessee. In the Cumberland Mountains, which in this region form the western wall of the valley, there is a gap called Cumberland Gap. It is close to the place where Virginia, Tennessee, and Kentucky join. The gap provided an easy passage in the mountain wall, through which the wagons of the early emigrants made their way into the forested country of Kentucky. For many years after the Revolutionary War one family an hour, on the average, drove through this gap seeking a new home to the westward.
274. Limestone and roads.—The Great Appalachian Valley became the great high way for several reasons. First, it is nearly level, and therefore easier to travel upon than is the Piedmont where there are hills, or the Coast Plain where there are many deep rivers to cross. Sec
ond, limestone is plentiful here, and out of no other stone can good roads be made so easily. The Great Valley, therefore, has many miles of good stone roads.
If you have read about the battles of Antietam and Gettysburg in our own Civil War, you can see how this valley was the roadway by which the Southern armi went north and the North ern armies went south.
275. Limestone and val ley making.—Indeed, it was limestone that made the Great Valley. Once upon a time, a very long while ago, the whole region was a plateau. Limestone wears away or dissolves in water (Sec. 22) more easily than does any other stone. For this reason the lime stone district has been worn down more quickly than the hard sandstone, and therefore has a lower surface. In this way the limestone strips became valleys, and the strips of harder stone remained as ridges. (Figs. 236, 241.) 276. Limestone and limestone rock of which the valley floor is made breaks up into a very fertile clay soil, which is good for wheat, corn, and hay. Many of the people of this region make their living by farming, and the rich valley fields are covered with grain or dotted with grazing animals. Each year fat cattle and great quantities of corn, wheat, and dairy produce are shipped to the cities of the north and east.
277. Limestone and is a raw material that goes into the iron fur nace along with iron ore and fuel. Much West Virginia limestone is sent from the Great Valley to the Pittsburgh iron furnaces.
The early settlers found iron ore in many places because limestone sometimes helps to cause deposits of iron ore. In the early days many mines were worked and a great iron making industry developed, but after a better grade of ore was found in northern Michigan and Wisconsin (Sec. 334) most of the Great Valley mines were closed. Iron fur naces still thrive at Bethlehem, at Lebanon, and near Harrisburg in Pennsylvania; at Roanoke in Virginia; at Birmingham in Alabama, and at other places.