The gneiss landscape west and north of Bergen viewed in profile can remind us of a saw blade of the kind that has long, slanted sides that get broken off shorter transverse sides. It has taken several hundred million years to file this saw blade, an enduring interplay between various geological processes.
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.
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.