The mountainous peninsula Tjornes is indented with short valleys and gorges. It is situated between the bays Skjalfandi and Oxarfiord. In the east it is steep and in the west and along the coastline it is more undulating and lower. There, the lower sandbanks characterize the landscape and almost work like a vade-mecum for those, who are interested in geology. The alternating strata of sand and deposits are either totally devoid of any sign of life or contain compact layers from the Pliocene and the late ice age, fossilized marine life. These strata confirm the opening of the Bering Strait (probably at the end of the tertiary or the beginning of the ice age), connecting the two great oceans, the Pacific and the Atlantic.

Among the fossilized shells are specimen from the Pacific Ocean, which could only have travelled through the Strait in earlier times. These strata also show lava layers, river deposits and moraines, which depict the changes of the climate, the sea and land fauna and the flora. The thickness of this strata measures about 500 m but the total thickness amounts to about 1200 m. The oldest stratum was found between the rivers Kaldakvisl and Reka. There one can find alternating strata of lignite and sea shells.

The Hallbjarnarstadir strata shows fossils of extinct shell species and species, which only thrive in warmer waters further south. The lignite was mined during the time of the second world war. The lignite strata irrefutably depict the fact, that there were coniferous forests in Iceland along with spruce, oak , beech, platan and other species, which can not be found any more. When we get closer to River Hallbjarnarstadaa there is a reduction in the species, which are susceptible of colder climates. Instead one can find species of shells still surviving off the Icelandic coast, many of which were brought through the Bering Strait.

The Tjornes strata also bear witness to the different status of the sea levels and that the ice age commenced about 3000 years ago with at least 10 differently extended warm periods in-between. Close to the farm Mana is a forest of antennas, which were put there by Japanese scientists to watch the northern lights (aurora borealis). Many travellers stop to watch the seafowl at Engidalsgja and watch the view from the eastern edge of the peninsula at Audbjargarstadir.