On the northern side of Snæfellsnes from Kirkjufell west to Skarðslækur there are traces of up to 50 meters thick sediments. In these strata at cape Búlandshöfði there have been found cold-sea species such as Portlandia arctica, Leda pernula, the wrinkled rock-borer (Hiatella arctica), Tridonta montagui and Tachyrhynchus erosus (eroded turretsnail). At the bottom of the layers at Búlandshöfði, however, there are warm-sea species such as mussels, Arctica islandica (ocean quahog) and common periwinkle. Most of the evidence suggests that the strata at Búlandshöfði was formed at the end of a glacial period and at the beginning of the following warm period. Age analysis of the layers indicates that oldest ones are about 1.1 million years old.