northwest corner of the State, and forms part of the boundary with New Brunswick.
Climate. Maine lies in the heart of the temperate zone, yet in climate it ranks as boreal in the northwestern part, and the southeastern part is only a region of transition into the austral zone—a region of overlapping floras and faunas. The winter is very severe, except in a narrow strip along the coast. The summers are never hot. The mean temperature for January is 20° F. and 10° in the north. In July the mean temperature is 65° F. in the north and 70° in the south. There is a wide range of temperatures through the year, the average maximum shade temperature of 90° F. occurring all along the coast to Eastport. The anticyclones and north winds of winter bring an average minimum of 20° F. below zero to Eastport and Augusta, while the vicinity of Mount Katahdin records an average minimum of 30° below zero. The weather is subject to sudden falls in temperature in short periods because of the frequent passage of cyclonic and anticyclonic centres and the subjection of the State to alternate oceanic and continental influences. The southern counties have a growing season of less than six months, and the northern counties of only about five months. The average annual rainfall for the whole State is 40 inches, very evenly distributed throughout the year, though there is a maximum precipitation in the late summer and autumn. There is an average annual snowfall at the coast of 60 inches, increasing rapidly to the north and west to over 110 inches. The relative humidity for the whole State is above 70 per cent., though the absolute humidity is rather low, on account of low temperatures. The normal wind direction for January is northwest, and for July is southwest. The State lies in the zone of maximum cyclonic frequency. The cool summers, the lakes, the forests and the rocky seaside attract multitudes of summer tourists, and the coast and lakes are lined with summer cottages. Some of the resorts, notably Bar Harbor, on the eastern end of Mount Desert (q.v.), are among the most popular of the American summer resorts.
For Flora and Fauna, see these paragraphs under United States.
Geology and Soils. Maine has had a very complex geological history. In pre-Cambrian time the State was crossed by two great mountain ranges. One extended along the northwestern boundary through the White Mountains to Long Island Sound east of the Connecticut River; the other extended northeast, along the coast. These mountains were much folded, largely gneissic and schistose, and they were worn down to base level in later Paleozoic time. Through the centre of the State, between these two ranges, a long gulf extended from Gaspé Peninsula to the southwest. By the end of Devonian time this trough was filled with sediments from the aging mountains, only to be uplifted, crumpled, and somewhat metamorphosed, again worn to base level and depressed, allowing carboniferous deposits to be laid down unconformably upon all the older beds. It was uplifted and again worn to base level in Cretaceous time, since which the region has been broadly lifted into a plateau of low elevation and again dissected. The Pleistocene ice sheet covered the State entirely, discharging its marginal ice into the sea. The effect of glaciation was to denude the higher lands, accentuate the river valleys, create many lake basins, and leave the surface strewn with a coating of till. Since Pleistocene time there has been a considerable subsidence, resulting in the submergence of the coastal lowlands, and converting the higher hills and ridges into a fringe of islands, and the drowned valleys into fiords. The latest crustal movement has been a very slight uplift along the coast, uncovering small plains of marine clays which interlock with the rocky headlands. This same slight uplift has revived the rivers, furnishing very valuable water power at the bay heads.
The soils of Maine, with the exception of the Pleistocene marine clays along the coast, are almost wholly glacial. Along some of the rivers and lakes and in many old lake bottoms, long since filled up or drained out, there are alluvial plains of great fertility. The higher outcrops of the crystalline old land are largely denuded of all soil, while the whole surface of the State is more or less strewn with glacial débris. The drift is in places arable, though in wide areas it is unsuited for agriculture. The character of the soil and the large supply and even distribution of rainfall have been determining factors in making the State a rich forest region.
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 transportation 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 occurs in great veins or in eruptive masses. Some of these were cooled very slowly, evidently at great depth, the crystalline structure being so extremely coarse that the quartz and feldspar constituents can be separated easily and marketed pure. Maine is one of the leading sources of feldspar and silica, used in the manufacture of earthenware, porcelain, glass, flour and wall tile, wood-filler, sandpaper, and scouring soap. The output of silica in 1899 was valued at $50,336, the supply 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 production of this commodity. In the central part of the State valuable slate quarries are worked for roofing, tables, and blackboards; the output in 1899, valued at $181,766, 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 crystals 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 importance, 10 of these being in Androscoggin County. In this year 1,850,132 gallons were
