[9] The sandstone is stained by a thin outer layer of deposited metallic oxides that colour the rock formations variously from near-black to dull red.

[9] Erosion in the area has resulted in nearly 300 natural rock arches being formed in the south east, along with deep gorges and permanent water pools in the north.

Due to the higher elevation of the area, coupled with the water-retentive properties of the sandstone, the vegetation here is somewhat more lush and verdant than in the lower regions of desert; in turn, this creates an attractive habitat for numerous animal species, from the smallest invertebrates, up the food chain to mammals.

[3] An isolated population of the West African crocodile survived in Tassili n'Ajjer until the twentieth century; today, the species is primarily found in more tropical and sub-Saharan regions of Western and Central Africa, from Senegal to Chad.

[11] Algerian rock art has been subject to European study since 1863, with surveys conducted by "A. Pomel (1893–1898), Stéphane Gsell (1901–1927), G. B. M. Flamand (1892–1921), Leo Frobenius and Hugo Obermaier (1925), Henri Breuil (1931–1957), L. Joleaud (1918–1938), and Raymond Vaufrey (1935–1955).

"[12] Tassili was already well known by the early 20th century, but Westerners were broadly introduced to it through a series of sketches made by French legionnaires, particularly Lieutenant Charles Brenans in the 1930s.

[13] Lhote's expeditions have been heavily criticized, with his team accused of faking images and of damaging paintings in brightening them for tracing and photography, which resulted in reducing the original colors beyond repair.

[16] There are numerous rock shelters within the sandstone forests, strewn with Neolithic artifacts including ceramic pots and potsherds, lithic arrowheads, bowls and grinders, beads, and jewelry.

[3] The transition to pastoralism following the African Humid period during the early Holocene is reflected in Tassili n'Ajjer's archaeological material record, rock art, and zooarchaeology.

Paleoclimatic and paleoenvironment studies started in the Central Sahara around 14,000 BP and then proceeded by an arid period that resulted in narrow ecological niches.

[21] The rock art at Tassili is used in conjunction with other sites, including Dhar Tichitt in Mauritania,[22] to study the development of animal husbandry and trans-Saharan travel in North Africa.

[27] Among the 15,000 engravings so far identified, the subjects depicted are large wild animals including antelopes and crocodiles, cattle herds, and humans who engage in activities such as hunting and dancing.

The Round Head Period is associated with specific stylistic choices depicting humanoid forms and is well separated from the Archaic tradition even though hunter-gatherers were the artists for both.

The scenes reference diversified communities of herders, hunters with bows, as well as women and children, and imply a growing stratification of society based on property.

[33] The image depicts a female figure with horns in midstride; dots adorn her torso and limbs, and she is dressed in fringed armbands, a skirt, leg bands, and anklets.

The use of bull horns is a common theme in later round head paintings, which reflects the steady integration of domesticated cattle into Saharan daily life.

[35] In 1989, the psychedelics researcher Giorgio Samorini proposed the theory that the fungoid-like paintings in the caves of Tassili are proof of the relationship between humans and psychedelics in the ancient populations of the Sahara, when it was still a verdant land:[36] One of the most important scenes is to be found in the Tin-Tazarift rock art site, at Tassili, in which we find a series of masked figures in line and hieratically dressed or dressed as dancers surrounded by long and lively festoons of geometrical designs of different kinds... Each dancer holds a mushroom-like object in the right hand and, even more surprising, two parallel lines come out of this object to reach the central part of the head of the dancer, the area of the roots of the two horns.

[38] According to Brian Akers, writer for the Mushroom journal, the fungoid rock art in Tassili does not resemble the representations of the Psilocybe hispanica in the Selva Pascuala caves (2015), and he doesn't consider it realistic.