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.
In the region of Ulven phyllite occurs with Hordaland's youngest fossils, and a beautiful quartz conglomerate. The phyllite and conglomerate got squeezed into the bottom of an ancient oceanic crust, made of gabbro and greenstone, in the heart of the Caledonide mountain chain.
On Sandviksfjellet there are old boulders that have been made into mountains. The stones have been stretched out or squeezed together between huge slabs of rock, during slow, but powerfulprocesses of transport. This conglomerate shows, in quite a special way, the enormous powers that were active during the collision between Norway and Greenland over 400 million years ago.