278. Limestone and is a raw material used in cement-making. There are cement plants at several points along the valley. The greatest cement center is in the Lehigh Valley, near Allentown and Bethlehem. (Fig. 204.) In that local ity the industry is especially flourishing, because the great port cities of Philadelphia and New York are only about a hundred miles away. These port cities use much cement, and they ship quantities of it overseas.
279. Rivers.—Certain parts of the Great Valley have local names often taken from a river draining that section. Near the Delaware River it is the Lehigh Valley; in northern Virginia, the Shenandoah Valley; the part between the Susquehanna and the Potomac is called the Cumberland Valley. Name a town in each of these sections. Before there were railroads, the rivers that flow out of the Great Valley were most useful to farmers. They were the highways along which wheat, by much hard labor and risk of wetting, was taken down in flatboats to the fall line. The flatboat has been displaced by the rail roads. Which river of the Great Valley is now navigable for boats? (Fig. 80.) 280. Towns and town Great Valley gives us a good chance to study how towns grow. A town often begins at a place where there is some local advantage, such as a deposit of some mineral, rich farming land, or some other natural resource. The town becomes a city when the locality is favored with a large degree of one or more of these advantages and has, in addition, easy communication with the outside world.
The Great Valley has no large cities like New York, Philadelphia, or Baltimore, but it has many smaller ones. A town or a small city is to be found at almost every place where railroads cross the Great Valley and enter the plateaus to the westward, or the Piedmont to the eastward, because cross roads are good places for people to meet and to buy and sell goods. At such places stores, shops, and garages are built, and villages grow.
The cities of Allentown and Bethlehem are situated where the advantage of natural resources is combined with that of ease of communication. Look at the map (Fig. 204) and see how the Lehigh Valley enables rail roads to pass out of the Great Valley into the coal fields. These two cities are throb
bing with manufacture and busy with cement, iron, and steel mills.
The thriving city of Reading is at the place where the Schuylkill River gives an easy route to Philadelphia. The city of Harris burg arose where the Susquehanna Valley makes a break in the highlands. (Fig. 15.) There the main line of the Pennsylvania Railroad from Baltimore to Buffalo crosses the line from Philadelphia to Pittsburgh.
What would you say caused Hagerstown, Roanoke, and Knoxville to grow larger than the small towns near them? (Fig. 21.) Why does Chattanooga have such an excellent location? The largest of all the Great Valley cities is Birmingham, Alabama, which, although it is in the Cotton Belt, is also at the southern end of the Great Valley. (Fig. 21, dotted lines.) Here we find a rare thing hap pening: this one place has the three things needed to make iron. They are coal, iron ore, and limestone. Nearly every where else in the world one at least these things has to be carried long distances to the place where one or both of the others are found. At Birmingham you can stand at one place and see the mouth of the coal mine, the quarry for the limestone, and the open pits in the hillside from which the iron ore is being dug. At no other place in the world can iron be made so easily. So Birmingham, busy with its iron furnaces, has grown very rapidly. It is now as large as Richmond, Virginia, but its English namesake still far surpasses it in size.
At Chattanooga there are iron and steel plants, machine shops, wood-working plants, and cotton mills. In any large town in the Great Valley may be found one or more such plants.
281. Future of the Great Valley.—The towns of the Great Valley have many things to make them prosper. The local mines and quarries have plenty of material for cement plants and iron furnaces; the mountains can furnish wood; the plateau to the westward can furnish coal; and the railroads that come through from the south can bring cotton for the spinning, weaving, and knitting mills that are already established in many valley towns. The rich valley land can be made to yield much greater quantities of food if town markets demand the milk, fruits, and vege tables.