On the small, flat island of Mors in the Limfjord, the cliffs are not made of chalk or granite but of a pale grey-white clay, laid down in the sea about fifty-five million years ago. This is the moler, a deposit of diatom earth interleaved with hundreds of thin layers of volcanic ash, and it is one of the best places in the world to find fossils from the early Eocene. Fish, insects, birds and plants have been found here, beautifully preserved, including the bony fish that give the site its name.
The ash fell from volcanoes in the area that is now the North Sea, and it settled on a warm, shallow sea where life was abundant. The fossils are fine and detailed, and the layering makes it possible to count the ash falls, like pages in a book. The moler was also dug for industrial use, as an insulating and absorbent material, and old pits around Mors and the island of Fur are part of the story. Fossil collecting at the cliffs is regulated, so it is best to follow local rules and ask at the museum.
Mors is a quiet and green place. The roads run across low, rolling farmland, with small villages, windbreaks and long views over the fjord, and the surface is generally good. The corners are few, so it is a ride of space and sky rather than of bends, and wind is the main factor, especially on exposed coastal sections. The bridge to the island is a pleasure in itself, and a small ferry to the island of Fur is a short hop away.
Nykøbing Mors, about eight kilometres away, is the main town, with nearly ten thousand people, a good range of shops, fuel and restaurants. Thisted, a little further, is larger. Danish food here includes fresh fish, smørrebrød, and the local beer from Thisted, and the cafés are good for a coffee and a pastry.
The ride links these cliffs with the Viking-age ring fortresses, particularly Fyrkat, so you move from a deep past of fossils to a recent past of kings. The best months are late spring and early autumn, when the light is long and the crowds are small.