Saddle (landform)

{{Short description|Land connecting two high points}} [[File:Bergsattel.jpg|thumb|upright=1.4|Cross-section diagram of three hills, with two saddles marked by X.<br/>{{bull }}There are three peaks (''Schartenhöhe'') or [[prominence]]s shown labeled''' 'A', 'B', & 'C''''.<br>{{bull }} The diagram illustrates the [[topographic isolation]] (German: ''Dominanz'')-''the distance from a prominence which is also a minimum to the point of the same height''.<br>{{bull }} The 'isolation' (German: ''Dominanz'') of the right two peaks is not labeled, but is represented by the dashed line.<br>{{bull }} "sattel zwischen" means ''saddle between'', so the labeling is saying the saddle ''between A and C'' is the same saddle as ''between A and B'' ]] [[File:Saddleroute3.JPG|thumb|Route along a saddle]] The '''saddle''' between two hills or mountains is the region surrounding the [[saddle point]], the lowest point on the line tracing the drainage divide connecting the peaks. When, and if, the saddle is navigable, even if only on foot, the saddle of a (optimal) [[mountain pass|pass]] between the two [[massif]]s, is the area generally found around the lowest route on which one could pass between the two summits, which includes that point which is a mathematically when graphed a [[Maxima and minima|relative high]] along one axis, and a [[Maxima and minima|relative low]] in the perpendicular axis, simultaneously; that point being by definition the col of the saddle.{{citation needed|date=May 2018}}

==Topography== [[File:Wildspitze (r., top) with saddle Mittelbergjoch and ski lift in front.jpg|thumb|left|The saddle ''Mittelbergjoch'' (lower edge, left from middle) in Tyrolia in [[Austria]]. It is frequently crossed by [[Mountaineering|mountaineers]] on the way up to the [[Wildspitze]] (3.768 m, right upper corner). In the diagram top right, the saddle is comparable to the leftmost drawn type.]] A saddle is the lowest area between two highlands ([[prominence]]s or peaks) which has two wings which span the divide (the line between the two prominences) by crossing the divide at an angle, and, so is concurrently the local highpoint of the land surface which falls off in the lower direction. That is, the [[drainage divide]] is a ridge along the high point of the saddle, as well as between the two peaks and so defines the major reference axis. A saddle can vary from a sharp, narrow gap to a broad, comfortable, sway-backed, shallow valley so long as it is both the high point in the sloping faces which descends to lower elevations and the low area between the two (or three or four.{{efn|See the center image '''point '-C-'''' in the [[topographic]]al map image.}}) flanking summits. Concurrently, along a different axis, it is the low point between two peaks, so as such, is the likely 'optimal' high point in a pass if the saddle is traversed by a track, road or railway.

[[File:Cliffs Saddles Traverses Passes Ascents & Peaks-- from Sources of Nesquehoning creek from hzlt93sw-Rot90cw,_LargerType.png|thumb|upright=1.8|USGS topographic map of ridges and saddles near Hazelton, Pennsylvania (closer view). The points -A-, -B-, -C-, -D- and, -E- all represent saddles — relative minimums oriented to two or more nearby peaks, but a local maxima relative to lower land.]]

===Saddles and cols=== The relationship between saddles and [[col]]s is not universally agreed upon. A col is sometimes defined as the lowest point on a saddle co-linear with the drainage divide that connects the peaks. Whittow describes a saddle as ''"low point or col on a ridge between two summits"'',<ref>Whittow, John (1984). ''Dictionary of Physical Geography''. London: Penguin, 1984, p. 464. {{ISBN|0-14-051094-X}}.</ref> whilst the [[Oxford Dictionary of English]] implies that a col is the lowest point on the saddle.<ref>Soanes, Catherine and Stevenson, Angus (ed.) (2005). ''[[Oxford Dictionary of English]]'', 2nd Ed., revised, Oxford University Press, Oxford, New York, p. {{ISBN|978-0-19-861057-1}}.</ref> Monkhouse describes a saddle as a ''"broad, flat col in a ridge between two mountain summits."''<ref>Monkhouse, FJ (1965). ''A Dictionary of Geography'', 2nd edn.</ref>

The term col tends to be associated more with mountain, rather than hill, ranges.<ref>Chambers 21st Century Dictionary, Allied.</ref>

The height of a summit above its highest saddle (called the [[key saddle]]) is effectively a measure of a hill's [[Topographic prominence|prominence]], an important measure of the independence of its summit. Saddles lie on the line of the [[drainage divide|watershed]] between two [[hill]]s.

==Structural geology== In [[structural geology]], a saddle is a depression located along the axial trend of an [[anticline]].<ref>{{cite web |url=https://www.academia.edu/1266034|title=Glossary of Structural Geology |access-date=15 May 2016}}</ref>

==Mathematical saddles== {{main|Saddle point}} A 'saddle point' in [[mathematics]] derives its name from the fact that the prototypical example in two dimensions is a [[surface (mathematics)|surface]] that ''curves up'' in one direction, and ''curves down'' in a different direction, resembling a riding [[saddle]] or a [[mountain pass]] between two peaks forming a landform saddle.

== Notes == {{notelist}}

== References == {{Reflist}}

[[Category:Landforms]] [[Category:Oronyms]] [[Category:Structural geology]]