This central volcano, decorating the landscapes of the Breiddalur Valley and the vicinity of the Berufiord Bay, is ancient and extinct. The British geologist George D. L. Walker thoroughly researched this and other similar areas in the East. The landscape is dotted with large and colourful rhyolite intrusions and five prominent mountain peaks.
The southern slopes of the Breiddalur Valley are especially colourful with very irregular strata and thick layers of tephra. This central volcano stretches between Mt. Fossarfjall to the south of the Berufiord Bay to the north to Mt. Baejartindur. The western side stretches along the so-called Ofaerunafir, but the eastern side has been eroded away.
Around the middle of the volcano, the tremendous heat transformed the basaltic rock and andesite and left it green in colour, making it very difficult to distinguish between and the rhyolite. The row of mountain peaks was created later, when the rhyolite intrusions took place and created bulges in the landscape. This central volcano is considered younger than the so-called Alftafiord-central volcano and the Reydarfiord-central volcano.