Two types are distinguished: pre-colonial and Christian. Pre-colonial graves are round stone cairns of varying size. Christian graves are elongate and oriented (roughly) east-west and often though not always with a headstone at the west extremity. Settlements and grave sites are significant and often highly visible features of the archaeological landscape in the Namib. Most of these sites are less than 1,000 years old and they often contain important material evidence of desert subsistence strategies. Grave sites may be construed as evidence of traditional land ownership.