FJORD or FIORD (fyawrd) is the name given to a narrow arm of the sea which runs far inland and with more or less pre cipitous sides. The term is of Norwegian origin and is the name given to the characteristic sea lochs of the coast-line of that coun try. Fiords differ from normal river estuaries in that their channels are long, straight and narrow, with steep parallel sides which plunge far below the level of the water, and from which side arms of a similar shape branch off at constant angles. Fiords are remarkable for their depth, Messier Channel (Patagonia) is 4,25o ft. deep, and Sogne Fiord (Norway) is 1 oo m. long and ft. deep, but their deepest portion is always at some distance from the sea, very shallow water occurring at their mouths. Loch Moran (Inverness, depth 1,017 ft.) is a typical fiord but is separated from the sea by land 3o ft. above sea level. Fiords lie in deeply dissected plateau lands so that above the precipitous walls are gentle slopes and wide valleys. J. W. Gregory (see Nature and Origin of Fiords, London, 1913) dis tinguishes three types of sea estuaries, fiords, as here described, rigs and fiords.
Several theories have been put forward to explain the forma tion of fiords. A controlling factor in the formation of these theories has been the distribution of fiords and their occurrence in recently glaciated regions. Fiords do not occur widespread but appear to be situated around the polar regions, in Norway, the west coasts of Scotland, Ireland and Iceland, Greenland, Alaska and British Columbia, in Patagonia, the south of New Zealand and in several Antarctic lands. Sea erosion, glacial action or river denudation are not sufficient of themselves to account for the phenomena. The most probable process appears to have been as follows. Fiords occur in regions which have suffered faulting within geologically recent times, the faults being numerous and generally in more than one direction. Such faulting occurred in regions of tension and was accompanied by regional uplift, and in consequence river activity was increased and quickly reduced to base level a new river system which followed the lines of weakness set up by the faulting. The uplift and faulting took place before the Glacial Period, probably during the Pliocene, so that glaciers as well as rivers have played their part in fiord formation and modification. The latest stage has been subsidence and in some places tilting and the drowning of the river valleys by the incursion of the sea. Fiord coastlines are noted for their beauty. In the past they have provided an easy—frequently the only—means of communication for the people in many districts and have tharef ore played an important part in the development of racial and national characteristics.