covered in the extreme west by the carboniferous formation. In addition to these there are intrusions of eruptive rocks running in a chain of dikes east of the Blue Ridge. During the Eocene and Pleistocene periods the eastern part of the State was subjected to repeated changes of level, whose net result was the formation of a system of river valleys and their partial submergence into Chesapeake Bay and its branching estuaries.
Mineral Resources. The most valuable mineral resource of Maryland is coal, which is the best quality of bituminous and occurs in three areas known respectively as the Cumberland, Georgia Creek, and Frostburg ‘basins.’ One bed, the ‘Big Vein,’ is 14 feet thick, with others of less value below it. The area of the fields is more than 500 square miles. The output in 1901 was 5,113,127 tons, valued at $5,046,491, giving Maryland the twelfth rank among the States. Useful minerals are most numerous in the crystalline rocks of the Piedmont region. Here are many fine building stones, and there are found also, but mostly in unprofitable quantities, ores of copper, gold, chrome, lead, zinc, and iron, besides flint, feldspar, kaolin, and mica. The absence of large cities has limited the quarry industry to the region near the head of Chesapeake Bay. Of building stone for commercial use the State's output was $1,174,181 in 1901. Fine granite quarried near Port Deposit and Baltimore and marble from the vicinity of Baltimore have been used for the Government buildings at Washington and for important structures in New York and Philadelphia. Valuable clays are widely distributed, Baltimore County alone possessing clays suitable for building-brick, firebrick, pottery, stoneware, terra-cotta, sewer pipe, and paint. Natural cement is an important article of manufacture. The clay output is small, but the value of clay products is high, owing to the pottery and other clay manufactures of Baltimore, and the firebricks of the coal region, which are reported to be the best in the country. Potable waters of excellent quality abound; springs are numerous, and there are some mineral springs of local repute.
Fisheries. In 1897 Maryland ranked second only to Massachusetts in the value of its fisheries product. However, the industry has declined greatly since 1891, the value of the catch in 1897 amounting to $3,617,306, as compared with $6,460,759 in 1891. More persons are engaged in the industry than in previous years or in any other State, the number in 1807 being 42,812. The oyster catch amounts to about 80 per cent. of the entire product and exceeds that of any other State. The rivers flowing into Chesapeake Bay contribute largely to the fisheries products, particularly shad. The other more important varieties taken are crabs, alewives, striped bass, and white perch.
Agriculture. There is 81.9 per cent. of the land area of the State included in farms, and of this 68 per cent. is improved. The acreage of farm land increased 11.6 per cent. during the last half of the century, and there was a still greater increase in area of improved land. During the same period the number of farms more than doubled, while the average size decreased nearly one-half—the average in 1900 being 112.4 acres. The farms operated by owners amount to 66.4 per cent. of the total number. The proportion of rented farms is increasing, particularly the farms rented on the share method, which amounted to 24.8 per cent. of all farms in 1900. Only 12.7 per cent. of the farms are operated by colored farmers, while the proportion of renters among these is much larger than among the whites, and the average size of the farms is much smaller among the former than among the latter.
The area devoted to cereals in 1900 was considerably larger than it was in 1890, but almost the same as in 1880. Corn and wheat have almost equal areas devoted to them. In both cases there was an increase during the decade 1890-1900. As compared with 1850 the product of wheat more than doubled in amount, while the increase of corn was only a little less pronounced. Frederick County, in the Piedmont region, is the largest producer of these cereals. The area devoted to oats decreased more than one-half during the census decade 1890-1900. Other cereals raised in small amounts are oats, buckwheat, and barley. Hay and forage crops rank next to corn and wheat, both in the area devoted to them and the value of the product. A much smaller acreage is devoted to tobacco, but its large per acre value makes it one of the important crops of the State.
The lighter soils throughout the eastern part of the State are largely devoted to the raising of vegetables and fruits. In 1900 the value of the vegetable products, including potatoes, sweet potatoes, and onions, amounted to 15.2 per cent. of the gross farm income. Maryland canned a larger amount of tomatoes and sweet corn than any other State. There were 43,612 acres devoted to tomatoes, and 16,575 to sweet corn. The region south and east of Baltimore is noted for its peach orchards. In 1900 the peach trees numbered over 4,000,000 and constituted 60 per cent. of all fruit trees, although there was a large decrease as compared with the number at the beginning of the decade. There was a large increase during that decade in all other varieties of fruit trees. In the same year 17,516 acres were devoted to small fruits, of which about four-fifths were strawberries. Floriculture is extensively developed in the vicinity of Baltimore. Gardening and fruit-raising have given rise to the extensive use of fertilizers. The increasing demands of the growing centres of population have given rise to a large dairy industry, and the number of dairy cows increased from 86,856 in 1850 to 147,284 in 1900. The greater intensiveness of cultivation and increased use of machinery have necessitated more work horses, and the number of these has nearly doubled in the period mentioned. The following comparative tables give the more important crops and the number of domestic animals for the census years 1890 and 1900 (figures for crops given in acres):
| CROPS | 1900 | 1890 |
| Corn | 658,010 | 586,817 |
| Wheat | 634,446 | 510,727 |
| Oats | 41,625 | 99,195 |
| Hay and forage | 374,818 | 372,626 |
| Tobacco | 42,911 | 20,274 |
| Potatoes (Irish) | 26,472 | 24,987 |
