122 NAUTICAL CHART MANUAL 



Foothill One of the lower subsidiary hills at the foot of a mountain, 



or of higher hUls. (Commonly used in the plural.) 



Fork One of the major bifurcations of a stream ; a branch. 



Fracture zone A zone of unusually irregular topography of the sea floor 



averaging 60 nautical miles in width and normally greater 

 than 1000 nautical miles in length. This zone is character- 

 ized by large seamounts, steep-sided or nonsymmetrical 

 ridges, troughs or escarpments. 



Oap A deep notch, ravine or opening between hills or in a ridge or 



moimtain chain; a steep-sided depression cutting tran- 

 versely across a ridge or rise. 



Geyser A spring which throws forth intermittent jets of heated water 



or steam. 



Glacial gorge A deeply cut valley in U-shaped cross section, resulting from 



glacial erosion. 



Glacial lake A lake, the basin of which has been carved by glacial action; 



also-a body of water held in place by the damming action of 

 a glacier. 



Glacial drift Sand, clay, or boulders transported by glaciers to their present 



locations. 



Glacier (C-3) A field or body of ice, formed where snowfall exceeds melting 



and moving down a mountain slope or over a wide area. 



Glade A grassy opening or natural meadow in the woods; a small 



park. Applied in western Maryland to a bushy, grassy, or 

 swampy opening in the woods. 



Glen A secluded and small narrow valley ; a dell, dale or vale. 



Gorge A canyon ; a rugged and deep ravine or gulch. 



Grade A slope of uniform inclination. 



Gradient Any departure from the horizontal ; a grade ; a slope ; a part of 



a road or railroad which slopes upward or downward; fre- 

 quently used in connection with the slope of streams. 



Groin (G-11) A narrow shore-protection and improvement structure project- 

 ing out from the shore, buUt usually to trap littoral drift or 

 retard erosion of the shore. 



Grotto A small, picturesque cave, vault, or cavern. 



Gulch A small ravine ; a small, shallow canyon with smoothly inclined 



slopes and steep sides. 



Gulj A part of an ocean or sea extending into the land, usually 



larger than a bay. 



GuUy A small channel recently cut by running water; smaller than 



a gulch or ravine. 



Gut A narrow passage or contracted strait connecting two bodies 



of water. 



Hammock Variation of hummock, but usually characterized more by soil 



type and vegetation than by elevation. (Southern U.S., 

 esp. Fla. and Gulf Coast.) 



Harbor A water area nearly surrounded by land or artificial dikes 



forming a safe anchorage for ships. 



Head A headland or promontory. 



