MINERAL RESOURCES AND MINING. The fact that the surface is largely made up of the bases of worn-down old mountains explains at once the nature of the mineral resources of Maine. Granite rock outcrops all along the coast and for many miles inland. The fiords are incised in it, making it possible often to load the blocks on to the boats direct from the quarry. This fact of convenience and cheap transportations is a large factor, explaining the rank of Maine as second of all the States in granite production, the output in 1889 being valued at $1,321,182. The granite oc curs in great veins or in eruptive masses. Some of these were cooled very slowly, evidently at great depth, the crystalline structure being so extreme ly coarse that the quartz and feldspar constitu ents can be separated easily and marketed pure. Maine is one of the leading sources of feldspar and silica, used in the manufacture of earthen ware, porcelain, glass, flour and wall tile, wood filler, sandpaper, and scouring soap. The output of silica in 1899 was valued at $50,336. the sup ply occurring as vein quartz in the crystalline rocks. Along the coast in occasional places and in Aroostook County and other places in the interior, are found beds of crystalline limestone, often a fine quality of marble. The value of the
limestones, including the marble, was in 1899 $1,028,375, giving the State the sixth place in the eroduction of this commodity. In the cen tral part of the State valuable slate quarries are worked for roofing, tables, and blackboards; the output in 1899, valued at 8181.766, ranked the State fourth in this resource. The total value of quarry products in 1899 was $2.531,223. The crystalline rocks of Maine produce many rare minerals, one of which, tourmalin, is obtained in Oxford County in larger and more beautiful crys tals than anywhere else in the world. Copper, silver, gold. iron, tin, and manganese occur in small amounts, the iron and manganese being used only in local smelters. The State reported 26 mineral springs in 1899 as of commercial im portance. 10 of these being in Androscoggin County. In this year 1,850,132 gallons were marketed with a value of $179,450. Potable waters of the highest quality are found in great abundance everywhere, the glacial drift being the usual source of supply for domestic use.