Roughly 550 million years ago, what is now Finse lay at the bottom of the sea - the remains of mud and clay that were deposited in this sea have ended up on the roofs of Norway. Also the thrust sheet from the continental collision has found its way to Finse, after a several hundred kilometre-long, trek through the mountains, that took several tens of millions of years to complete.
There are coal bits hidden in the sand under Vatlestraumen. These remains from a geological layer from the Jurassic Period were discovered when the undersea Bjorøy Tunnel was built in 1994. Oil- and gas reservoirs in the Troll Field in the sea west of Hordaland are from the same time. It is, nonetheless, quite surprising to find bedrock from dinosaur time inside of the outer islands of western Norway. On the Scandinavian mainland north of Denmark, there are only a very few places where one f inds rock from this time in earth history.
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.
At Spjutøy and Straumsosen there are three entrances from Lurefjorden to the fjord basin inside. Right up the end of the 1800s the ferry could not reach further than to Mølna at Spjutøy. At Skallestraumen there was a bark mill driven by the powerful tidal current in the sound. Here was also a store, a bakery and a hostelry place around the middle of the 1800s.