This is one of the more interesting outcrops of rhyolite in the region. On top of the rhyolite is an excellent section of tillite and interglacial basalt flows. Turn off route 54 on the gravel road to Mávahlíð farm, now abandoned. You will drive through Mávahlíð and past the abandond farms Tröð and Fagrahlíð. Continue up the valley, along the river and stop where “park” is shown on the map. Rhyolite is all around you here. Hike down into the canyon directly in front and follow it up stream. The multicolored yellow, brown and red rhyolite has intruded Tertiary basalts and its age is probably around 3 million years. When you reach the lower falls (marked “falls” on map) then scramble up on the right side of the falls, in the rhyolite scree. Continue up the gully until you see the spectacular upper falls (“upfalls” on map). Here the rhyolite intrusion has been eroded by glacier action, forming a perfectly flat surface on top of the light grey to yellow rhyolite. This is overlain by about 1 to 2 meter thick layer of tillite. On top of the tillite is a basalt lava flow with perfect columnar jointing. The basalt has in turn been eroded on top. When you return you have two choices. You can backtrack the way you came, or you can be adventurous and climb up the north side of the canyon. Then you come on to a 4x4 track, which will lead you down back to your vehicle.