Page:The National geographic magazine, volume 1.djvu/52

Representative Geographic Forms as classified by Genesis.

Genetic Processes.			Geographic Forms.
Category.		Class.
Deformation	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$	Elevation	Continents, great islands, most mountain ranges, etc., not classified in detail.
		Depression	Oceans, great seas and bays, some inland valleys and lake-basins, etc., not classified in detail.
Gradation	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Deposition	Newly emerged ocean-bottoms (e. g., portions of the Coastal plain), playas and mountain-bound deserts, many flood-plains, marshes, etc., not classified in detail.
		Degradation	Drainage-systems and resulting topographic elements which are— 1—Autogenous (not classified in detail); and 2—Tectonic— Consequent, upon Displacement before emergence, and Sudden displacement after emergence; Antecedent; and Superimposed, through Sedimentation, Alluviation, and Planation.
Vulcanism	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Extravasation	Volcanic peaks, craters, lava-fields, tufa-crags, sinter-cones, volcanic necks, mesas, dykes, some mineral veins, etc., not classified in detail.
		(Antithesis of do.)	Sinks, caverns, some fissures, etc., not classified in detail.
Alteration	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Lithifaction	Minor features of certain topographic forms, e. g., reefs, crags, pinnacles, salients, out-cropping veins, some cataracts, etc., not classified in detail.
		Delithifaction	Minor features of certain topographic forms, e. g., pools and basins, reëntrants, some fissures and caverns, etc., not classified in detail.
Glaciation	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Glacial construction	Drift-plains, moraines of whatever character, drumlins, kames, aasar, drift-dammed lakes, loss-plains and ridges, etc., not classified in detail.
		Glacial deconstruction	Rock-basins. U-cañons, roches de moutonnées, etc., not classified in detail.
Wind action	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$	Wind construction	Dunes, sand-ridges, bars, spits, etc., not here classified in detail.
		Wind deconstruction	Ponds associated with dunes, "blow-outs," "purgatories," etc., not classified in detail.
Vital Action	|	(Not discriminated)