By Jozef Saers
Today not much more than a gravel pit remains of the excavated site of Västerbjers, Gothem parish on eastern Gotland. The site consists of a settlement and a cemetery, both dating to the Pitted Ware Culture (PWC) of the Middle Neolithic. It is just a pit in the ground, but Västerbjers is a central place in the archaeological literature (Malmer 1962, 2002; Janzon 1974; Löfstrand 1974; Österholm 1989; Andersson 1997, 1998). The settlement at Västerbjers has been mapped by Inger Österholm, using the phosphate analysis (Leijonhufvud 1989:37), and it extends in some places to the banks of the river Gothemsån, measuring c. 500x350 m in diameter. The partly excavated burial ground, being c. 100x60 m, is situated on the small end of a spur near the river. The ceramics from the site dates from the Middle Neolithic to the Bronze Age. The Stone Age ceramics from the settlement do not differ from the burials and there are a few huts excavated near the burials. Some post holes and fireplaces may belong to the burials and the rites for the death. Today a farm still occupies the southern part of the settlement area, so most of the settlement can not be excavated (Leijonhufvud 1989). The catchment area of Västerbjers has been studied by Helena Andersson (1998). Nearby is the Mesolithic settlement at Svalings, and further to the east is another settlement at Gothemshammar ( Appelgren 1989), with its causewayed enclosure. Within a range of 20 km of the site, more than 12 settlements are known, which makes this region the densest populated of the 14 catchment areas area on Gotland according to Österholm (1989:164 ff.). In such 20 km large catchment areas the livestock can move freely. By culling the herds of animals it will be difficult to tell, simply from the bone remains, if the cows, horses, pigs or sheep really were domesticated. Christian Lindqvist writes about an one time import of all these animals during the early Neolithic ( Lindqvist, 1997,373). Jan Ekman studied pig bones from PWC settlements, at Ire and Gullrum and he concludes that they are not domesticated (Ekman 1974:216). On the other hand he mentions that horses should be thought of as domesticated since they are of the size of the present day Gotland pony (Ekman 1974:218). “Harvesting the sea, farming the forest” would be a suitable way of describing life on Gotland in the Middle Neolithic, as the title by Marek Zvelebil et al. (1998) suggests. During the Stone Age as well as today there where wild horses of the breed Gotland pony grazing freely on the inland of Gotland, mainly at Lojstahed. These breeds are not so strange, as appears, since the human skeletons of the Gotlandic PWC show a cruralindex indicating the people came from northern Russia ( Ahlström 1997,334-335 ) and maybe the use of zinken at some Danish PWC settlements ( Becker 1982,29) also indicate a migration from the same direction. Seriation of artefacts from the graves.
When Mårten Stenberger (1943,68) published his monograph from the excavations at Västerbjers he included a tabulation of 50 inhumation graves with the different categories of artefacts in a logical ordering and the grave finds in number order The tabulation of all these excavations can of course be regrouped. For the purpose of doing some reasoning about the find material it would be good to have the different arguments following each other. Graphically it would be seen as a close collection of markings along a diagonal, where the different arguments can be said to follow upon each other. Depending on the artefacts and its grouping, it could be about chronology, the younger following upon the older, or after richness, social groupings etc. In archaeological collections of artefacts the time factor is often eminent, whether we like it or not, because of the long time spans we can see in the material. A reordering of the tabulation has been done according to a principle, which has been has been presented in earlier writings (Saers 1978). It just reorders the columns and rows by sorting after the most extreme markings. There are some restraints in this method. Distinguishing between different amounts of a certain type must be done by splitting it in different “types” according to different groupings of quantities. Also every row and column must have at least occurred twice, otherwise it is not a combination. This way of working by iterative reordering can be done by a computer and a programme written by the author has been used. Other, more statistical methods based on averages have been presented by Ihm (1980) and Scollar (1988), and a lot of others also exist, see Baxter (2003). For some philosophical views of time seriation, see Normark (2004: 54 ff.). After the adding of complementary grave finds found in Janzon (1974:335 ff.) and Wyszomirska (1984:275), the result of the reordering is presented in Figure 1.<
Figure 1. burialnr: 1 6 68 60939340000593033666682170840247378810 17314626518959934532682093034401726712 concave edged axes x x x x x battle axe x harpoons with 2 teeth x x x x comb impressed ceramic xx x x flint axe, 1p xx x x xx x decorated bone points x x x deer antler axe x x flint arrowheads x x x x harpoons with many teeth x x x flint blades xx x x x bone plaques x x plain ceramics x xxxx xxxx x x x x boar tusks, 2 - 3p x x xx x rock axe x x x x x xx x x xx amber beads x x x boar tusk, 1p x x xx x x x flint axes, 2p xx xx x x bone points x x x boar tusk scrapers xx xx x x x tubular beads, 1 - 10p x x x x x xx xx boar tusks, 8 or more x x x pitted ware ceramics x x bone points, 1 - 2p x xx xx x x x tooth beads, 1 - 6p x x x x x x tubular beads, 11p or more x x tooth beads, 7p or more x xxxx xx x seal teeth x x x x xx x chisel x x fish hook x x boar tusks, 4 - 7p x x x bone ornaments x x x bone arrow heads x x slate points x xx
The seriation diagram shows a broad band with find combinations. This grouping is done with less logical precision than the one given in a table by Mats Malmer (1962:728-729, 2003:94-96). Still even the above can be divided in the same manner, only differing in detail. The burials from Malmer’s southern burial ground at Västerbjers are found in the upper, left side of the table, and those from the northern part on the opposite side. Both ways of ordering the artefacts gave almost the same result, but when the find combinations are presented as a band, it is difficult to conclude that there are two different burial grounds, instead it appears to be a more gradual development. This is of course a consequence of the method used and does not hide the fact that the upper, older part of the site has less of natural, local material and more of stone- and flint axes.
The absolute dating with radiocarbon , given by Eriksson (2003:6 ff.) is summarised in Figure 2.
Figure 2. BP grouped columns, number Burial number: 0 5 10 15 20 25 30 35 4350 H . . . . . . . 61 4300 . . . . . H . . 80 4250 . . H . . . H A 65, 67:2, 87 4200 . . . . . . H . 67:1 4150 . . . H H . . . 4, 88 4100 . . H . . . HA H 24, 65, 87 The letter H indicates samples taken from human bone, while A is taken from animal bones. All dates are uncalibrated with errors between 40 and 70 years. If any timeline can be read out of this tabulation it goes from the upper left to the lower right corner.
Taking due care for the measurement errors means that every radiocarbon date can be placed a little higher or a little lower, in the row corresponding to be 50 years older or 50 years younger. The dating differences, when using the radiocarbon dating method, between the human bones and the animal bones in burial 30 are rather small, only c. 30 years. The greater differences in dates from burials 65 and 87 are a little more than 100 years apart so these radiocarbon dates could be reconciled, or within their error spans of both dates, or be placed together halfway between and the time-line would be easier to spot. When transforming the radiocarbon dates into calendar years the wiggles of the calibration curve can make a date of c. 4100 BP to be from c. 3000, 2650 or 2600 BC. On the other hand the period of c. 4350 to 4200 show very small wiggles, still this older part show the same spreading of dates, in the above tabulation indicated as the "plateau" period. So no clear picture emerges out of this study. Building a chronology on wiggle period dates, i.e. placing all radiocarbon dates in the consecutive wiggle periods was done by Furholt (2003), where the whole period, from c. 4600 BP to c. 3600 BP, is divided into eight periods. But statistics being statistics, i.e. one French skeleton was dated by two radiocarbon dates, these vaying with 145 and belonging to two different wiggle periods (Furholt 2003:16). A more accurate dating can be obtained if the seriation is regarded as chronologically relevant. Then the different burials placed in columnar order can be assumed to be like year rings in a tree, which allows an approximate time line to be drawn through the wiggles of the radiocarbon dates and the time span to be between 3000 BC and 2600 BC. No calibration programme is used, because the different radiocarbon dates are used in connection with their places in the columnar ordering taking care of their places in the virtual stratigraphy of the seriation. The burial 62 placed in column 30 would then be date to c. 2800 BC. Eriksson combined the dates in two groups following Malmers division and found the two resulting combined probability distributions to overlap ( Eriksson 2003,24), and hence no chronological division in the time period 2840 – 2580 BC. This long time period is still only part of the total life span of the Pitted Ware Culture in eastern Sweden, which covers c. 3900 BC to 2150 BC ( Edenmo & Olsson 1997,183).
From the seriation it is however possible to see that the people at Västerbjers in early times had access to axes of flint and other stone material and several other kinds of import goods such as amber, tusk shell (Dentalium spp.) and bone plaques. Later on smaller chisels are used together with slate and bone points (Taffinder 1998). The battle axes, one Danish undergrave-axe from burial 39 and the other a Swedish D:1a-axe from burial 7 belong to the early phase as does the axe of basaltic rock from northern Germany in burial 36 (Stenberger 1942:115). The later burials in the seriation indicate a trade from the mainland of Sweden with import of slate artefacts ( Taffinder 1998,129ff) and the emerging unifying Late Neolithic culture. The relative paucity of import goods in the later parts would then indicate other preferences in the Neolithic society. The traders of Gotland could take advantage of the islands location in the middle of the tic Sea, in combination with its fertile soil, where wild animals also thrive. Becker (1950:249 ff.) sees the Pitted Ware Culture in Denmark as the remnants of traders, still a strong theme discussed by Inger Österholm (1989:185 ff). That people living on an island has to be fishermen and seal hunters from that it is easely taken for granted they were used to sea voyages. The wear signs on some of the skeletons from Ire, Hangvar parish on northwestern Gotland, indicate the same way of life (Gejvall 1974:165 ff.). People, during the Middle Neolithic period, maybe even buried their dead in dug out canoes as a possibility proposed by Gunborg Janzon (1974: 22).
The Pitted Ware Culture settlement and burial ground at Västerbjers on Gotland is re-examined in order to find a better, inner chronology. A seriation method was used and for the radiocarbon dates wiggle periods are taken into consideration. The radiocarbon method have limitations due to the plaeau effect of the wiggle periods. For a more detailed chronology, groupings of artefacts and seriations can give an finer chronology than radiocarbon datings alone can give. A better chronology also gives us a better ground for understanding the ever ongoing changes in society, past and present.
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