Region 7, as shown on our map, contains the nonforested or lightly forested subhumid areas in Texas and Oklahoma, where the climate is mild enough for cotton. It extends from semiarid regions 2 and 4 on the west to the humid regions 8 and 12.

We draw its eastern boundary so as to include within it the Texas Black-land Prairies, except the poorly drained prairie along the coast. In Oklahoma we include the Crosstimbers and their intermingled prairies, but exclude the Ozark and Ouachita Mountains.

8a and 8b. THE MISSISSIPPI DELTA AND COASTAL PRAIRIES differ from their neighbors in having predominantly low-lying, naturally poorly drained soils. They contain the bottom lands and terraces of the lower Mississippi Valley and the wetter Coastal Prairies of Louisiana and Texas. They include the soils on which rice is grown outside of California. The soils mostly are fertile, although poor drainage and (in some places) floods limit their productivity.

9. THE MIDLAND FEED REGION Combines productive soils, gentle relief, and moderate rainfall over a wide area. Summers are warm, but winters are cold. Nearly all rural land is farmed, and a higher percentage of the total land area is cropped than in any of the other regions. Steep slopes or poor soils in some localities interrupt the generally productive areas that characterize the region, but they are much less extensive than in the other regions.

Feed crops predominate. All but the northern part is in the Corn Belt. Most of the feed is fed on the farms where it is produced, but some areas specialize in growing feed to sell.

Region 9 is more humid than regions 5 and 6. It has a longer frost-free season than region 10 and generally more productive soils. It has a shorter frost-free season than region 11, fewer areas of steep slopes and poor soils, and much more land that requires drainage. Region 14, which touches region 9 on the northeast, differs from region 9 in having a much greater amount of stony, shallow, steep, or otherwise poor soils, and in having somewhat less sunshine and greater humidity in summer.

10. THE NORTHERN PART OF THE LAKE STATES has cool summers, cold winters, moderate moisture, and diverse soils. It sometimes is called the Lake States Cutover region. In contrast to region 9, its neighbor to the south, most of the land has not been converted to farming but remains in forest.

Poorly drained soils, some of them peat bogs, are widely distributed.

These and deep sands, stony soils, shallow soils, and productive, well-drained soils are more or less intermingled in region 10. Parts of the region have soils and climate similar to some parts of region 14, but the two regions are physically separated, have different complexes of physical features, and therefore lend themselves to separate consideration here.

11. THE EAST-CENTRAL UPLANDS comprises a moderately warm, humid region north of the Cotton Belt and south of the Midland feed region. Diversity of soils and relief is characteristic. The diversity is more extreme than that of its neighboring regions 9 and 12.

Its soils range from the highly productive, phosphatic, limestone-derived soils of the Blue Grass and the Nashville Basins to the steep, stony soils of the southern Appalachians. The region has warmer and more open winters than regions 9 and 14, which adjoin it on the north. It is colder and has a shorter frost-free season than region 12 to the south; the boundary between them approximates the cold limit of cotton production. It lacks the extensive areas of wet or swampy soils, found in region 15 to the east, and also lacks the sandy soils found in parts of that region. It is more humid than region 6, which touches it on the west.

12. THE SOUTHEASTERN UPLANDS REGION has a warm, humid climate, generally well-drained soils, and gentle to moderate slopes. It is split by the Mississippi Delta (region 8). It differs from region 11 in that its climate permits Cotton to be grown, and from regions 8, 13, and 15, in lacking the extensive poorly drained areas found in those regions. It is more humid than region 7 and has much forest land.

The ridges of the Ouachita Mountains in the northwestern part of the region are an exception to the generally gentle to moderate slopes.

13. THE FLORIDA PENINSULA AND ADJACENT COASTAL FLATWOODS REGION is a humid region of mild winters and long, frost-free seasons, which permit the production of subtropical and early-season vegetables. It is characterized also by a preponderance of low-lying, poorly drained soils, although most of the intensive farming is not on these soils, but on the better drained soils. This predominant poor drainage further distinguishes this region from the Southeastern Uplands (region 12).

14. THE NORTHEAST, as we have delineated it here, is probably distinguished from its adjacent regions more by its predominant type of farming than anything else, although it is cooler than regions 11 and 15. Dairying is its most important farming enterprise, and we have drawn its boundaries approximately along the line where other types of farming become more important. A soil boundary suitable for separating this region from region 11 is hard to find, although the soils gradually change in some of their characteristics as we pass from one region to the other.

15. THE MIDDLE ATLANTIC COAST, the Atlantic Coastal Plain from Long Island to South Carolina, is used mostly for intensive, high-value crops, like vegetables, tobacco, and peanuts. It contains large areas of poorly drained soils and some deep, dry sands, which are largely in forest. It differs from region 14 in its lack of stony soils, its gentler relief, and its frost-free season; from region 11 in its large amount of poorly drained soils; and from region 12 in its greater prevalence of poorly drained soils and in the predominance of other enterprises than cotton.