Maize, which requires a higher summer temperature and a greater rainfall than wheat, is grown in large quantities in the southern parts of the North Central States. Western Ohio, Indiana, Illinois, and Iowa produce over 30 per cent. of the maize crop of the United States, and along with Missouri, Nebraska, and Kansas, where decreasing precipitation accounts in part for a smaller yield per acre, they produce considerably more than one-half of the output of the whole country.
Since 1890 the area under maize has increased from 35,000,000 acres to about 60,000,000 acres, a result largely due to the growth of the live-stock industry. Many cattle are reared in the region, and many others are drafted in from the Great Plateaus, as far south as Texas, to be " finished " for market. The rapid growth of population, both in the North Central and in the Middle Atlantic States, has greatly increased the demand for meat and dairy produce, while the development of transport and the use of refrigerating cars have made it easy to meet that demand. The number of cattle in the region under consideration cannot be determined exactly, but it is probably about 32,000,000 (United States 70,000,000). Hogs are even more concentrated in the maize belt, and over half of the entire number in the United States (48,000,000) are found within it.
Over 70 per cent. of the slaughtering and meat packing of the United States is done in the North Central Region, where the industry is to the maize belt what the manufacture of flour is to the wheat fields. Chicago is the chief city engaged, and produces nearly 30 per cent. of the country's output. It owes its pre-eminence, on the one hand, to its suitable position for receiving live stock from the whole of the north-west, and, on the other, to its facilities for distributing the manufactured product. Kansas City and South Omaha, which practically do nothing else, have become of considerable importance within recent years with the extension of the corn belt in Nebraska and Kansas ; and East St. Louis, St. Joseph, and Indianopolis has each a large output. With the excep tion of New York, which produces one-twentieth of the whole, the leading cities in this industry are in the maize-growing states.
In addition to its great agricultural resources, the North Central Region has much mineral wealth, and three large coalfields of Carboniferous age lie within it. The most important of these is the Eastern, which covers most of Illinois, the south-western corner of Indiana, and a small portion of Kentucky. The output of this
field amounts to over 65,000,000 tons, or rather more than one-seventh that of the United States, and the coal from it, besides supplying a large contiguous manufacturing area, makes its way down the Mississippi as far as Louisiana, and westward into the Dakotas, Nebraska, and other states. The Northern coalfield, which lies in the centre of the lower peninsula of Michigan, has an annual output of over 1,000,000 tons, much of which is used locally, but some of which goes westward into Minnesota and the Dakotas, as a return cargo for the cars bringing wheat eastward. The Western coalfield extends over parts of Iowa, Kansas, Missouri, Oklahoma, and Arkansas, the portion within the region under consideration producing about 20,000,000 tons annually, most of which is used locally, either by the railways or for domestic purposes.
In the North Central Region, as in the Allegheny Plateau, the horizontal nature of the strata has led to the conservation of large supplies of petroleum. The chief fields are those of western Ohio and Indiana, of Illinois, and of Kansas—the latter extending into Oklahoma and northern Texas. The production of the first is decreasing, that of the second is steady, while the third has an output considerably greater than the first and second combined. The production of the whole region amounts to rather less than half that of the United States, which yield two-thirds of the world's supply. Pipe lines convey the oil from Illinois to the Atlantic seaboard, and that from Kansas to the Gulf. Natural gas is obtained in Indiana and Kansas, but the production is decreasing.
The principal localities in North America which at present produce iron ore may be considered as falling within this region, although they really belong to the Laurentian Plateau, of which they form outlying parts. Over 80 per cent. of the iron ore obtained in the United States is mined in the neighbourhood of Lake Superior, where the chief districts in which it is found are the Mesabi Range in Minnesota, to the west of Lake Superior, the Vermilion Range, a little to the north of the Mesabi, the Marquette, in the upper peninsula of Michigan, and the Menominee and Gogebic Ranges further south, on the borders of Michigan and Wisconsin. The total production for 1910 was 40,000,000 tons, of which 30,000,000 came from the Mesabi Range.