Ezo layers refer to geological layers stretching from Cape Soya in the north to Urakawa Town in the south of Hokkaido. These layers were deposited in the sea chiefly in the Cretaceous Period. Near the layers are municipalities known for a treasure trove of fossils, such as Nakagawa Town, Obira Town, Mikasa City, Yubari City and Hobetsu, Mukawa Town, where various fossils including those of ammonite and elasmosaurus were discovered. Above all, Hokkaido is Japan’s largest production site of ammonite, and is also famous for the number of large-sized ammonites ever found.

photo courtesy: Hobetsu Museum