430 million years ago, the Earth looked very different than today. The continents had a completely different shape and location than in our time. At this time, in the Silurian period, Norway was located south of the equator and was flooded by a shallow and warm sea, which provided perfect conditions for life. Many of the creatures strolling around in the ocean at this time, had developed outer shell or inner skeleton of lime. Over the years, these has effectively been fossilized and turned into limestone, a widespread rock in the area.

The typical fossils found on Kapitelberget are different types of corals, crinoids and sponges. You can also find fossils in the building blocks that forms the foundation of the medieval church, as they are derived from the area just around Kapitelberget.