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VIRGINIA 375 for miles, with a thickness of from 10 to 100 ft. The manganese in some of the ores renders them valuable for the manufacture of Besse- mer steel. Copper pyrites are abundant in the gold belt, where carbonate of copper is also found. Large quantities of the ore of sulphuret of copper are obtained in Louisa co. Copper, chiefly in the form of sulphurets, abounds throughout the Blue Kidge range. Mines have been worked in Floyd, Carroll, and Grayson cos. Some of the ores yield from 26 to 29 per cent. According to Prof. T. S. Hunt, u the mountains of the Blue Ridge contain deposits of sulphur ore as abundant as those of Spain." Lead abounds in many parts of the great valley; about 25,000,000 Ibs. have been taken from the mines in Wythe co. since 1T63. Zinc is found coextensive with the lead. Plumbago is found in Halifax, Amelia, and other counties. In middle Vir- ginia are beds of bituminous coal covering an area estimated by Rogers at 185 sq. m. The Richmond coal field, about 13 m. W. of Rich- mond, in the counties of Chesterfield, Pow- hatan, Henrico, and Goochland, is about 30 m. long, with a maximum breadth of about 8 m. It has been longer known and worked than any other in the United States, but its impor- tance has declined. Bituminous coal is also found in the S. W. part of the state, in the counties of Tazewell, Russell, Scott, Lee, Bu- chanan, and Wise, being a part of the great Ap- palachian coal field. Semi-anthracite or semi-' bituminous coal occurs along the western side of the valley division of Virginia. The coal is used only for domestic purposes, but its proximity to extensive iron beds may render it useful for manufacturing purposes. Marls and other agricultural minerals are abundant in the tidewater country. A great variety and abundance of building stones are found in nearly all parts of the state. Beds of gypsum of superior quality have been opened for more than 20 m. along the North fork of Holston river, in Washington and Smyth cos. In the same region salt is obtained from artesian wells about 200 ft. deep, the water rising to within 40 ft. of the surface. The brine comes from a solid bed of salt. The annual produc- tion of salt is about 350,000 bushels. Salt has also been made in the S. E. part of Lee co., on the Clinch river. Virginia abounds in natu- ral curiosities of great interest. The natural bridge in Rockbridge co. is one of the most remarkable natural arches in the world. (See BRIDGE, NATURAL.) Weyer's cave, in the N. E. corner of Augusta co., ranks among the stalac- tite caverns of the United States next to the Mammoth cave of Kentucky and Wyandotte cave in Indiana. Madison's cave, near it, about 300 ft. in diameter, has two extensive basins of very clear water, and from the vaulted arch- es depend great numbers of brilliant stalactites. The Blowing cave, near Millborough, between the Rockbridge and Bath Alum springs, during the hot weather emits a current of cold air with such force as to prostrate the weeds at the entrance ; and during the winter a current of the cold air from without rushes into the cave. There is a flowing and ebbing spring near this cave, and there is also one in Brocks's gap in Rockingham co., and another near the mouth of the North Holston in the S. W. part of the state, which Jefferson regarded as syphon fountains. The numerous mineral springs are for the most part in valleys sur- rounded by exquisite natural scenery. The climate varies greatly in different districts. In the E. and S. E. parts of the state the sum- mers are hot, and in the vicinity of swampy lands near the coast intermittent fever is com- mon. The region lying on and near Hamp- ton roads is however healthful and agreeable at all seasons of the year. The peninsular dis- trict between the James and York rivers, and between the latter and the Potomac, is spe- cially subject to miasmatic influences during the summer and early autumn months ; in win- ter it is more healthful. The valley of Vir- ginia has a salubrious and delightful climate, the summer heats being tempered by the ele- vation and the cool breezes, while it is shel- tered by the mountains from the intense cold of winter. The mountainous district generally has a very agreeable climate in summer, but portions of it are very cold in winter. In gen- eral the climate is mild, dry, and healthful. The length of the growing season, the distribu- tion of rain throughout the year, and the short and mild winters, are highly favorable to agri- culture. The following statement shows the results of meteorological observations at Nor- folk, lat. 36 51'; Lynchburg, lat. 37 23'; and Wytheville, lat. 36 56': PARTICULARS. Norfolk. Lynchburg. Wythevill*. Spring, mean temperature. 55-1 51-5 60-2' Summer, ' W 75-8 68'6 Autumn, " 58' 4' 65" Winter, " 44-3 40-5 Year, " 68 -4 56-5" 51-3 Mean annual barometer 80-08 80-07 29- 6 Annual rainfall, inches 55-27 44-74 40-66 The soil of the tidewater region is a light sandy loam, capable of yielding large crops of fruit and esculent vegetables ; but it has been to a great extent worn out by superficial culti- vation without manure, and many estates, once among the finest in the state, have been given up to dwarf pines and cedars. The free use of gypsum and marl, both found in great quanti- ties in the state, is sufficient in two or three years to restore these lands to a condition of high productiveness. In the vicinity of the Roanoke, the James, and their tributaries, large quantities of tobacco are raised. The valley has a rich soil, admirably adapted to the cultivation of cereals, and is in fact the gran- ary of the state. Much of the mountainous region is uncultivated, and some of it incapa- ble of tillage ; but the valleys between the par- allel ridges are generally well watered, and