Geology.—The state is occupied by azoic, mezozoic and paleozoie formations. The first prevails mostly in the south-eastern portions, crossed by the second in a hell; of about 2.5 in. in a line from New Jersey to Maryland; while the paleozoic marks the rest of the state. The latter may be found classified in the geological report of II. D. Rogers. Special localities indicate the presence of drift in the shape of gravel in the n. and n.w. tier of counties. Gneiss abounds in the s.e. portions of the state, and occupies a tract from Trenton to Philadelphia and up the Schuylkill; it runs through portions of Dela ware and Chester counties, traverses Northampton, Berks, Lebanon, parts of Lancaster, Danp'lin. and reappears in Adams co., where it meets a similar formation along the border of the state, within this tract are found marble quarries (Philadelphia), lead and copper (Pliamixvillo, nickel (Lancaster co.), magnetic Iron ore (Warwick, Cornwall, and other numerous points in Berks, Lebanon, and Lancaster counties); chrome iron ore is mined nr th- serpentine barrens near Octoraro creek, in Lancaster county. The lower Silurian iu Lancaster, Berks, and Lehigh counties, and many central sections of the state contains vast deposits of hematite iron. New red sandstone is found in a belt of country whose northern limits•stretell in a ling from Durham near the Delaware across the Schuylkill below Beading, and the Susquehanna below Harrisburg to near Waynesburg; while its southern limits run on a line from Trenton, Norristown,' hrough Lancaster co. into Adams county. Sandstohe, red shale, trap-rock, abound throughout the district; the sandstone is excellent for building purposes, and utilized for that purpose. The lower members of the paleozoic series above described dip n.w. under the auroral magnesian rover Silurian limestones, flanked by the Kittatinny and Blue mountains on the one hand, and the South mountain on the other. The entire region is very fertile, and embraces some of the richest agricultural districts of the state in the counties of North. anipton, Lehigh, Berks, Lebanon, Dauphin, Cumberland,and Franklin. A similar belt of limestone country runs through Lancaster co., and in part through York; a narrow band of the same formation traverses likewise Montgomery and Chester counties. Roofing slate is found, and extensively quarried in Northampton and Lehigh counties. Limestone areas, scattered in Montour, Clinton, Snyder, and Mifflin counties, and the Juniata valley, continuous in Centre co., extend also is a s.w. line, through Blair and 13ed(ord counties to the Maryland border. The upper Silurian and Devonian run u and n.w. to the Allegheny mountain. The ridges in well-marked •parallels, traversed by rivers. and diversified by fruitful valleys, present a scenery of romantic beauty and a subalpine character; and shows the different members of the gigantic paleozoic fornm don. The general features' of that hill-region are much the same to the Allegheny mountain, w. of which they are eutirelrchanged; round knolls, short and broken ridges, distinguish the bituminous coal region. . The coal measures c. of the Allegheny stretch in three parallel beds; the northern, from Carbondale through Scranton and Wilkes barre to the xv. of Newport; almost due s. of it, is found the Lehigh coal field: still further s.w. from Alnhanoy City, through Ashland and Shamokin, to within a short dis tance of the Susquehanna, lies the second or middle anthracite coal fields, while the southern, with Pottsville in the center, extends continuously from Manch Chunk, on the Lehigh. to Wiconisco, and by southern branch to within a short distance from the Susquehanna. The semi-bituminous coal field is in the region of the Broadtop moun tain in Huntingdon and Bedford countics.—Tte Allegheny mountain is the eastern limit of the vast bituminous coal fields, which overspreni the greater part of the western see thin of the state. Sandstone, iron ore, limestone, and fire-clay ham-stratify with the coal. Limestone occurs to a limited extent in the Allegheny but is found more copinosly in the upper portions of the Mononrtaliela. At Johnstown, Brady's Bend, and in Westmoreland and Fayette counties ironstone is mined: and the charcoal furnaces of Armstrong. Butler, and Clarion counties-absorb large quantities of limonite. See IRON.
Petroleum is found in prodigious quantities in Warren, Forest, and Venango counties, also in Mercer and Crawford counties, at a depth of 1000 ft. below the lowest coal formation of the district. It is likewise found at the confluence of the Monongahela and Cheat rivers. See PErrum.Eum. San wells are worked in the valley of the Kiskiminetas or Concinaugh river on an extensive scale; although that industry is capable of vast devel opment, us salt springs are not only very abundant in w. Pennsylvania, but exist in Susquehanna. Lycoming, Clearfield, and Bedford counties.—The mineral springs near
Bedford, much frequented and justly celebrated for their curative power, issue in the smite valley, at short distances from each other, are at least five in number; they are respectively, sweet, sulphureous, calcareous, chalybcate, and mixed. The last, Ander son's, is the most important and highly valued.
The rolling country of the western and central sections contain vast tracts of produc tive soil; Washington, Allegheny, Beaver, Fayette, and Indiana counties arc peculiarly rich for cereals; Mercer, Crawford, and Erie are better adapted for grass. The pres ence in uncleared regions of an abundance of white oak, hickory chestnut, walnut, and ash is an index to cereal fertility; beech, maple, and black ash indicate good grassland; while the prevalence of pine marks indifferent soil. The Alleghenies produce almost every species of timber except 'white oak. White pine, poplar, beech, sugar-maple, chestnut, and birch are most abundant. The first predominates chiefly on the eastern slopes of the mountains, wild cherry, walnut, hickory, and oak are frequent; chestnut predominates on the Chestnut ridge, and Laurel hill region, which yields also red and rock oak, In the valleys and along the water-courses, hickory, ash, sugar-maple, cherry, elm, and sycamore of majestic growth flourish. Sugar-maple and beech fill the forest in the vicinity of lake Erie, hemlock in Clearfield, Cambria, etc., beech in the Lehigh region. Fruit-trees of almost every species abound, and the grape is extensively culti vated. The culture of tobacco in Lancaster co. has of late years become extensive and profitable.
The climate of the state is different in its three natural divisions of eastern, western, and northern. The eastern section is marked by irregular alternations of the seasonst the mean extremities of notation for a great number of years being 5° below•zero, and 100' Fahr.; there are seldom more than 30 days of above 80° heat in summer, and below 35' in winter. Sudden changes are of frequent occurrence—intensely hot or cold weather seldom tests more than 3 days continuously. The period from the middle of January to that of February is generally the coldest, and from the beginning of July to middle of August the hotter~. In the western section the fluctuations are more abrupt, and heat and cold more excessive. In the northern section and the mountainous regions of the entire state the winters are very severe, with an extreme temperature' as low as 20° below zero; the summers delightfully cool. The climate is decidedly healthful, although malaria lingers in the river valleys, along canals, and in swampy regions.
According to the census of 1870, the manufacturing interests of this state place it first as to the capital invested, and the number of establishments, second only as to the value of products. Besides the leading industries of coal, iron, and petroleum (figures below), the minor ones in which the state ranked first in the United States included paper-bags, blacking, carriage trimmings, charcoal and coke, chromos, lithographs, dye-woods, stuffs and extracts, explosives and fire-works, glues, perfumery, cosmetics, fancy soaps. Likewise in building and roofing materials produced, and in lumber. The lumber shipments from the two chief emporia at Williamsport and Lock Haven.are enormous. Time agriculture of the state is very extensive. In 1870 the total number of farms, of an average size of 103 acres, was 174,041; it had 11,515,965 act-es of improved land in farms, 5,740,804 acres of woodland, and 737,371 acres of unimproved land. The total value of the farms was $1,043,481,582; of implements, etc., $35,658,196. The total value of all farm productiou S was $183,946,027; of orchard products, $4,208,094; of market gardens, $1,810,016: of forests, $2,670,370: of home manufactures, $1,503,754; and of animals slaughtered or sold for slaughter, $28,412,903. The productions in 1873 were: of Indian corn, 26,929, 000: wheat. 15,548,000; rye, 3 283,000; oats, 31.229,000; barley. 3,981,000; buckwheat, 2,022,000; potatoes, 10,602,000 bush.; 15.000,000 lbs. of tobacco, and 2,446,400 tons of bay, covering 5,780.917 acres, and valued at $115,965;700. In live stock the state num bered: of horses, 557,000; mules. 24,900; oxen and other cattle, 722,600; match cows, 812,600: sheep, 1.674,000; and hogs, 1,034,000, with an aggregate value of $116,911,954. The mineral products in 1874 were: coal, anthracite, 21,631,118; bituminous, 7.712,461; sumi-bittuninous, 2,303,461; and block, 500,000 tons. Petroleum (1870), 171,207,022 galls. Iron (1873), 913,085 tons in anthracite, 430,634 tons in bituminous and coke, and 45.854 tons in charcoal, furnaces. The other minerals produced were: copper, marble, nickel, slate, stone, and zinc.