See S. L. Boardman, _Climate, &c., of Maine_ (Washington, 1884); Walton Wells, _The Water Power of Maine_ (Augusta, 1869); G. H. Hitchcock, _General Report on the Geology of Maine_ (Augusta, 1861); G. H. Stone, _The Glacial Gravels of Maine and their Associated Deposits_ (Washington, 1899); T. Nelson Dale, _The Granites of Maine_ (Washington, 1907), being Bulletin 313 of the U. S. Geological Survey; B. F. De Costa, _Sketches of the Coast of Maine and Isle of Shoals_ (New York, 1869); H. D. Thoreau, _The Maine Woods_ (Boston, 1881 ); L. L. Hubbard, _Woods and Lakes of Maine_ (Boston, 1883); T. S. Steele, _Canoe and Camera, a Two Hundred Mile Tour through the Maine Forests_ (New York, 1882); William MacDonald, _The Government of Maine, Its History and Administration_ (New York, 1902); _Maine Historical Society Collections_ (Portland, 1831- ); W. D. Williamson, _History of the State of Maine_ (Hallowell, 1832); J. P. Baxter, _Sir Ferdinando Gorges and his Province of Maine_ (Boston, 1890) and _George Cleeve of Casco Bay_ (Portland, 1885); George Folsom, _History of Saco and Biddeford, with notices of other Early Settlements and of the Proprietary Governments in Maine_ (Saco, 1830); J. L. Chamberlain, _Maine, Her Place in History_ (Augusta, 1877); E. S. Whitin, _Factory Legislation in Maine_ (New York, 1908). FOOTNOTES: [1] This condition results from the fact that Maine and the adjacent region were worn down nearly to sea-level by stream erosion, except certain peaks and ridges inland; then the region was elevated and numerous river valleys were cut down below the general erosion surface formed before. Thus we have a general "upland surface," above which the mountain remnants tower, and below which the rivers have been entrenched. [2] This name is applied to a chain of lakes (the Rangeley, or Oquossoc, the Cupsuptic, the Mooselookmeguntic, the Molechunkamunk or Upper Richardson, the Welokenebacook or Lower Richardson, and the Umbagog) in Franklin and Oxford counties, in the western part of the state; the Umbagog extends into New Hampshire and its outlet helps to form the Androscoggin River. These lakes are connected by straits, have a total area of between 80 and 90 sq. m., and are from 1200 to 1500 ft. above the sea. They are sometimes called the Androscoggin Lakes. [3] The census of 1905 was taken under the direction of the United States census bureau, but the statistics for hand trades were omitted. [4] According to previous censuses the population was as follows: (1790) 96,540; (1800) 151,719; (1810) 228,705; (1820) 298,335; (1830) 399,455; (1840) 501,793; (1850) 583,169; (1860) 628,279; (1870) 626,915.