Rock-art generally struggles with two major problematic issues, chronology and interpretation, and the rock-art of Twyfelfontein forms no exception. Furthermore, especially an analysis of the cupules at Twyfelfontein will prove to be extremely complicated, as there seem to be too many differing cupule-traditions, each with too few examples, and each with its own array of possible interpretations. In general, a rock-art tradition denotes a coherent group of styles (e.g. geometric or iconic) that extends through time in a defined area. Therefore, in this paper, the term "cupule tradition" is only used to distinguish between the several much differing manifestations of cupules at Twyfelfontein. They differ so much in size, number, arrangement, orientation, age and association with other styles that it can be safely stated that there exists no one cupule tradition in this area.
The dating of rock-art at Twyfelfontein in general, and indeed elsewhere, is rather problematic, as obviously several rock-art styles exist at this extensive rock-art site, even on individual panels. Moreover, it is generally accepted that the engravings of animals could be up to 10.000 years old (Pager, undated: 22) or even older (see Whitley & Annegarn 1994; Thackeray  quoted in Ouzman 2001b: 239). Such an enormous time span indeed easily allows for several chronological rock-art layers to be present at one site or panel, as is also demonstrated by several instances of superimposition. Complicating things further is the fact that engravings may often have been reworked, so that the new pecking destroys the real age of the original figure. Of course, this also counts for cupules, which often are the oldest surviving elements in a rock-art region.
Indeed, the great age of some Twyfelfontein cupules seems to be confirmed by our discovery of the engravings at panel 1.1, where cupules clearly have been combined with simple geometric motifs. Both geometric designs and the (enclosed) cupules have the same deep patination, indistinguishable from the patina of the natural rock surface, and therefore they probably are of the same age. Moreover, the more protected these geometrics and cupules are, the more unweathered they appear.
Importantly, the engravings on this stone survived because of the protection of a large overlying block (A in Figure 4). It is so large and wedged-in that humans without mechanical aid cannot move it. The overlying block seems to be the top part of a series of three large boulders (A, B and C in Figure 4) that apparently once broke from the west face of the enormous west block, possibly during one event. However, theoretically, it is also possible that stone A fell upon the decorated surface much later. As the site is located on level land, it is impossible that running water caused block A to fall, but the initial impact may have created a weak spot in rock AB, which ultimately split so that block A fell upon stone 1.1 much later. It is also possible that this crack was caused by a stroke of lightning during one of the occasional heavy thunderstorms during the wet season.
On the west face of the enormous west boulder are some geometrics (and only three very doubtful cupules in an isolated position - see description of Site 1) as well as a few animal engravings. All these engravings could only have been executed if the vertical wall was accessible at that time. It is possible however, that this only was the case after the tumbling down of boulders A, B and C. But whenever boulder A fell upon stone 1.1, it is certain that the engravings on stone 1.1 already had been executed.
It therefore looks as if, in this area, the execution of the animal images and geometrics without cupules started after the overlying block came to a rest upon the decorated surface of panel 1.1. As it seems that the manufacturers of the animal images preferred (almost) vertical panels, they ignored the upper, almost horizontal surface of stone 1.1, although it cannot be ruled out that on the eroded part there once might have existed animal engravings (added at one time and worn off completely?). Therefore, the cupules and geometrics on panel 1.1 just possibly may represent the oldest surviving rock-art at Twyfelfontein. But the true chronology and the real sequence of events can only be ascertained by a scientific geo-chemical survey at the site.
Panel 1.1 seems to be the only pure example at Twyfelfontein of an (early?) geometric-cupule tradition. The situation at other panels is often obscured by graphic elements that may have been added later or even constitute a different cultural tradition. Panel 4.2 for instance features cupules of apparently different ages, together with clearly circular geometric designs, but also two figures with the same old patination (A and B in Figure 15) that look like elements of the non-cupule geometric style.
At Twyfelfontein altogether 37 rocks (rocks 2.2 and 5.1 are excluded as cupule stones - see Table 1, Appendix 1) proved to have (possible) cupules. However, most cupules at Twyfelfontein are found on panels featuring other rock-art traditions and at first sight, primordial cupules seem to be extremely rare at Twyfelfontein. The term "primordial" covers all instances where the cupule was the first and only rock-art element to be executed on a rock surface. I could spot only one boulder (4.3) with just one isolated small cupule and no other humanly marks, although the rest of the smooth vertical panel offers a suitable canvas for rock-art.
The general absence of rocks with apparent primordial cupules at Twyfelfontein seems to suggest that in this area there never existed a tradition to mark stones with only cupules. However, such a tradition might well have existed. Notably 25 rocks (marked with Y [yes] in Table 1, Appendix 1) just possibly could have started off as stones with primordial cupules (especially 4.4, 4.7, 4.16 and 4.20). But most of these 25 stones became unrecognisable as such by the accumulation of later iconic imagery. The other 12 panels with cupules (marked with N [no] or ? in Appendix 1, Table 1) involve instances where cupules seem to have been superimposed upon geometric or iconic art and therefore these cupules may represent later additions. However, it must also be noted that the cupules on some of those 25 panels (for instance 1.1 and 4.20) may always have been an inextricable element of a (very early?) geometric rock-art tradition.
Remarkably, there are relatively few stones with geometric art at Twyfelfontein (altogether 41 rocks: 15.3 % of my 2001 count of 268 individual decorated rocks at Twyfelfontein [see Table 2, Appendix 1] - Scherz counted 212 stones, 1975: 174). Only four rocks at Twyfelfontein have cupules on the same panel as geometric designs and animal imagery. One of these rocks, 4.1.6, features an oryx, which, according to Scherz (1975: 175), probably is a later addition. The "Fabeltier" at panel 4.12 almost certainly constitutes a later addition to the geometric designs, although Ouzman (2002) states that there are at least three geometric motifs placed partially on top of the "Fabeltier". All these "conflicting" observations prompt the necessity of a thorough survey of the dating of Twyfelfontein rock-art.
Importantly, both Scherz (1975) and Shirley-Ann Pager (undated, but published around 2001) agree on the idea that in general most geometric designs in Namibia are older than the animal engravings, also at Twyfelfontein. This may imply that especially the Twyfelfontein cupules that are firmly associated with geometric designs, or the cupules that originally started off as "primordial" cupules, may also be older than the bulk of the animal engravings.
It is surprising however, that there seem to exist two different geometric rock-art traditions at Twyfelfontein (and perhaps in a wider southern African area as well). One style involves the combination of cupules with mainly circular geometric designs (like at panels 1.1, 4.1.2 and 4.2), while the other generally omits cupules from its repertoire and its designs are less rigid. This latter group is represented at Twyfelfontein by only a few stones (for instance B7 and F29), which feature geometric designs (and sometimes [later?] iconic imagery, for example at B23), but, importantly, no cupules.
Although those two styles seem to differ stylistically (there is a notable contrast for instance between the mainly circular engravings associated with cupules on stone 1.1 (Figure 6) and the more (curvi) linear designs bereft of cupules on stone F29 (Figure 92), it is impossible to tell whether there is also a chronological gap between them without scientific dating. There is a possibility that both geometric traditions are contemporary, but nevertheless culturally distinct.
Latest research however seems to indicate the opposite: the later Khoekhoen herder peoples probably have authored most geometrics, not the ancestors of the San hunter-gatherers, who seem to be the manufacturers of cupules (Sven Ouzman 2002: pers. comm.) and of course of the animal imagery. This new view may not lead, however, to the conclusion that all geometric art at Twyfelfontein uncritically belongs to a Khoekhoen rock-art tradition, despite the fact that indeed Khoekhoen engravings are generally more crudely executed than San rock-art (for more discussion on the Khoekhoen engravings see Appendix 2: the Twyfelfontein Site Report by Sven Ouzman).