Generally in geology and especially in tectonics вал is arch, here, the Myldzha arch. Swell is an all-encompassing term for dome and arch. Examples:
Geological model of the Upper Jurassic deposits of Shaim ...
eurekamag.com/.../geological-model-upper-jurassic-deposits-shaim-meg...
Anonymous, 1993: Geological model of the Upper Jurassic deposits of Shaim mega-arch for oil recovery factor study.
Auris AG: African Geology

www.aurisag.ch/location/african-geology.html
African Geology ... Regional Geology and the Congo Craton Geology. ... into schists) on the southern flank of the mega-arch, Pre-Ituri palaeo-valley in particular, ...
[PDF]
Petroleum geology of East Siberia by James W ... - the USGS

pubs.usgs.gov/of/1985/0367/report.pdf
United States Geological Survey
U.S. Geological Survey editorial standards and stratigraphic nomenclature, ..... Bratsk high, 27 - Nepa arch, 28 - Anabar mega-arch, 29 - Sukhan depression,.

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Note added at 2 days15 hrs (2014-05-31 20:19:40 GMT)
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See also:
Structural traps

www.priweb.org/ed/pgws/systems/traps/structural/structural....
There are three basic forms of a structural trap in petroleum geology: ... is an example of rocks which were previously flat, but have been bent into an arch. Oil .