mud-coated mummies. He believed that these occurred chronologically, the mummification process becoming more complex as time went on. Since then, archaeologists have expanded upon this explanation and have (for the most part) agreed upon the following types of mummification: natural, black, red, mud-coated and bandage mummies. Mummification can also be described as externally prepared mummies, internally prepared mummies (Egyptian Pharos), and reconstructed mummies (the Chinchorro), according to Andean Archaeologists. Further, it turns out that the types of mummification used overlap with each other, and mummies of different types have been found all in the same tomb. The two most common techniques used in Chinchorro mummification were the Black mummies and the Red mummies. Natural mummification Of the 282 Chinchorro mummies found thus far, 29% of them were results of the natural mummification process (7020 BC-1300 BCE). In northern Chile, environmental conditions greatly favor natural mummification. The soil is very rich in nitrates which, when combined with other factors such as the aridity of the Atacama Desert, ensure organic preservation. Salts halt bacterial growth; the hot, dry conditions facilitate rapid desiccation, evaporating all bodily fluids of the corpses. Soft tissues, as a result, dry before they decay and a naturally preserved mummy is left. Even though the Chinchorro people did not mummify the bodies artificially, the bodies were still buried wrapped in reeds with grave goods. The black mummy technique The black mummy technique (5000 to 3000 BCE) involved taking the dead person's body apart, treating it, and reassembling it. The head, arms, and legs were removed from the trunk; the skin was often removed, too. The body was heat-dried, and the flesh and tissue were completely stripped from the bone by using stone tools. Evidence exists that the bones were dried by hot ashes or coal. After reassembly, the body was then covered with a white ash paste, filling the gaps with grass, ashes, soil, animal hair and more. The paste was also used to fill out the person's normal facial features. The person's skin (including facial skin with a wig attachment of short black human hair) was refitted on the body, sometimes in smaller pieces, sometimes in one almost-whole piece. Sea lion skin was sometimes used as well. Then the skin (or, in the case of children, who were often missing their skin layer, the white ash layer) was painted with black manganese giving their color. The red mummy