Holmengrå is the only place in Hordaland where we find traces of the abrasion that is supposed to have transformed Western Norway from a Himalaya-like high mountain landscape during the earth's Paleozoic Era, to a flat lowlands terrain during the Mezosoic Era. Just 400 million years ago, large and small stones plummeted down from the high mountains. Some of these stones became incorporated into the conglomerate bedrock on Holmengrå.
The peat bogs on Toska have been mined for peat since 1946, when the island got electricity. In this treeless coastal landscape, peat was the most important source of energy, and this took quite a toll on the bogs.
On Vågenes, on one of the prominences out toward Eitrevågen, one finds garnets in anorthosite. The garnets are both older, and not least bigger, than average.