Although in the past some archaeologists affirmed that these engravings derived from European Upper Paleolithic art, this theory is today definitively rejected.
The most important works are notably those of Auguste Pomel (from 1893 to 1898), Stéphane Gsell (from 1901 to 1927), Georges-Barthélemy Médéric Flamand (from 1892 to 1921), Leo Frobenius and Hugo Obermaier (in 1925), l'Abbé Henri Breuil (from 1931 to 1957), L. Joleaud (from 1918 to 1938), and Raymond Vaufrey (from 1935 to 1955).
In 1955 and 1964 Henri Lhote had visits of several months to the region which allowed him to complete his former researches, to add hundreds of new descriptions and in 1970 to publish Les gravures rupestres du Sud-oranais in the series Mémoires du Centre de recherches anthropologiques préhistoriques et ethnographiques (CRAPE) directed at Algiers by Mouloud Mammeri.
For Henri Lhote the South Oran region constitutes one of the "three great centres of art of the antelope age"[2]: 194 with Tassili ("Oued Djèrat") and Fezzan.
Auguste Pomel, relying on identification of an animal which Henri Lhote believes is a hartebeest,[citation needed] is at the root of the position of some authors who think that the engravings belong to the Palaeolithic age.
Presumably, the pictures which Pomel, Flamand and others identify as the recently extinct buffalo species Pelorovis antiquus,[3][4][5] is called "hartebeest" in the text of this article below.
Stage II, which he attributes to the Lower Neolithic, brings together the large ram of Bou Alem, the hartebeest, rhinoceros, elephants and other animals in less accomplished style.
[2]: 197 The author also thinks that the domestication of the dog was achieved in this period and that the South Oranian presents the most ancient rock testimonies to it.
All these engravings are made by a punctuation of little dots or hollows, more or less connected, and then most often by a polishing apparently helped by a wooden utensil with the addition of wet sand.
These naturalistic images show the same fauna (hartebeest, elephant and rhinoceros) as those of the preceding group but in very conventionalised forms, the legs and tails of the animals being very thinned out, the lines of the horns and the muzzle prolonged in a 'fantastic' way (Flamand), the lengthening of the body, the hind-quarters and the heads having inspired faulty identifications.
From a technical standpoint the finish of the engravings is regular, no trace surviving of a preliminary dotting-out, and the patina is similar to that of the preceding stage.
From a chronological viewpoint, a single station (Koudiat Abd El Hak) shows an indisputable over-drawing, a little antelope with attenuated legs being overdrawn by a large elephant, although another would appear to be later than it.
"Whichever solution may prevail", concluded Lhote, one should consider that the identity of the fauna in each of the two groups indicates that there could not have been a great lapse of time between them, and that, despite the variation of styles, one can ask oneself if they do not represent two expressions of one and the same art.
The domestic cow with long or short horns sometimes wearing little spheres dominates this stage, the fauna being composed otherwise of elephants, antelope and ostriches, while images of humans are rare.
For the author, "this bovidian civilization has certainly emerged from a Saharan milieu, but it has only made a very superficial appearance in the south Oran," following the tracks from the Hills of Ksour, having perhaps "another direct contact with the Sahara in the region of Brésina.
For F. Cominardi, analysing most recently the superimposition of engravings at "Koudiat Abd el Hak",[6] it seems accepted that the naturalistic large-scale stage and the naturalistic small-scale stage (the most ancient level being constituted of very tiny engravings, the most recent by works of slightly superior execution) were contemporary, at least within a single epoch, "the first not being extinguished before the second began."
Analyzing their possible relations, the author's conclusion is "that the Ram played a religious role of first importance to the south-Oranians, that its association with man, though he may have been in a praying position, should have been armed with an axe, shows that it certainly had the character of a divinity which one would ask things of and which one might, on suitable occasions, sacrifice.
"[2]: 180 This role, he adds, "is well attested in the two hartebeest stages of large and small scale, but disappears in the age of the decadent style where nothing of it remains except the mere vestige."
One should be able, according to Lhote, "to interpret this phenomenon as a radical modification in the behaviour of south Oranians, a real change, unless it represents the arrival of new human populations.
In the absence of discoveries in the region of neolithic human remains and of an adequate understanding of the ambiguity of the images, "one should avoid any absolute identification" or "definitive option".