Essentially, the story starts with the appearance of two north French ceramic traditions:
- a Breton tradition, featuring Late Castellic and related pottery, which appears in the west of Scotland (at Achnacreebeag) as part of the 'Breton, Atlantic' strand of Neolithisation and
- a North-French tradition, constituting one of a variety of regional styles of 'Chasséo-Michelsberg' pottery and which is known in Britain and Ireland as 'Carinated Bowl' pottery . (The justification for using this term to describe a tradition that encompasses non-carinated forms as well as carinated forms is explained in 2007; and note that there is still variability in other people's use of terminology, with some still using the obsolete 'Grimston' or 'Grimston-Lyles Hill' terms, or the over-vague term 'bowl (or Bowl) pottery'. This is to be discouraged as it leads to confusion.)
The origins of the Breton tradition lie in the Morbihan region of south-east Brittany, while the Carinated Bowl tradition is most likely to have originated in the Nord-Pas de Calais region of northern France, where excavations at Étaples have produced a close comparandum.
The distribution of these two traditions, in their initial form, does not overlap; the former is limited to the west of Scotland, while Carinated Bowl pottery use extends over much of southern and eastern Scotland, as far north as Caithness. As will be seen below, however, in its later variants there was 'cross-fertilisation' between the two traditions as potters shared design ideas. It should also be noted that there were parts of Scotland - the Outer Hebrides (and some of the Inner Hebrides), north-west Mainland, parts of western mainland Scotland and the Northern Isles - where pottery did not begin to be used until the late 38th or 37th century BC.
The Breton tradition is characterised by the use of thin-walled, fine-textured bipartite bowls (of Late Castellic style) with distinctive decoration: the example from Achnacreebeag has a 'rainbow' motif above the carination and a fringe of short vertical lines below. Also present in the simple passage tomb at Achnacreebeag were sherds of two other pots of Breton style, more simply decorated with stab designs. The Breton parentage of this pottery is very clear, with comparanda, for example, from a simple passage tomb at Vierville, Normandy - a pot which represents the northward movement, either of the vessel itself or of the ceramic style, from Normandy (Cassen 2011 ) - and from the funerary complex at Locmariaquer in the Morbihan area of SE Brittany (ibid.). The development and dating of Late Castellic pottery is described in Cassen et al. 2011 , from which it is clear that the assemblage at Achnacreebeag dates to between c 4300 BC and c 4000 BC. This is therefore the earliest pottery in Britain and Ireland, standing at the start of a tradition of using decorated bipartite bowls in the west of Scotland and in Ireland: later examples of this tradition, showing clear stylistic 'parentage' from its Late Castellic origins, are to be found in the Clyde cairns of SW Scotland (where Jack Scott termed them 'Beacharra Bowls') and in the court tombs in the north of Ireland (where Humphrey Case called them 'Ballyalton bowls': 1961). The longer-term development of this particular ceramic style has been traced by Sheridan (1995; 2003), where its persistence in Ireland to around the 36th century BC can be traced .
Petrological thin-sectioning of sherds from the Achnacreebeag pots (by Gwenaëlle Hamon, for Alison Sheridan), and comparison with Breton Late Castellic pottery, has unfortunately proved inconclusive in determining whether the former had been actual imports to Scotland; the fabric is so fine that there are too few lithic inclusions to allow a consideration of origins on that basis. However, further work on examining local clays may help in this enquiry. It seems likely, however, that it was the know-how to make this pottery, rather than the pots themselves, which moved from Brittany to Scotland. This will have been a totally new technology in late 5th millennium Scotland, and the skill with which the Achnacreebeag assemblage had been made means that it can only have been made by a skilled and experienced potter/s.
It should be noted that the objections that have been raised to the idea of a Breton ceramic tradition having been introduced to Scotland (Whittle et al. 2011, 808ff) are based on a misunderstanding of the ceramic sequence in Scotland, with the later versions of this pottery type (e.g. at Beacharra) being assumed to be the 'parent' of the Achnacreebeag pots. This is an error (as explained in Sheridan 2012), and in any case no plausible alternative explanation for the appearance of an entire ceramic tradition has been offered.
The Carinated Bowl tradition
This tradition features the use of carinated and uncarinated vessel forms, all undecorated (save for the occasional use of decorative finger fluting ). Sheridan has made a distinction between the earliest manifestation of this ceramic tradition, which she has called 'traditional Carinated Bowl [henceforth CB]', and subsequent developments, called 'modified (or developed) CB' (2007; note the importance of using capital letters to distinguish between the tradition and the vessel form). 'Traditional CB' pottery is markedly consistent (in fabric, form and finish) over a wide area in Britain and Ireland, whereas 'modified CB' shows regional variation as the process of 'style drift' led to changes, in different ways, at different rates, in different areas.
Large Carinated Bowl pot from Knocknab, Glenluce, Dumfries & Galloway. Photo: Alison Sheridan
'Traditional Carinated Bowl' pottery features carinated bowls in a variety of sizes and shapes , mostly (but not exclusively) fine-textured, and mostly thin-walled. Some are extremely thin - as thin as 4 mm in some cases - and the whole tradition is the product of skilled potters with over a millennium of experience in making pottery. As with the Breton tradition, its appearance in Scotland, probably during the 39th century BC, represents a wholly alien technology, and the skill with which this pottery was made shows that it was made by people who were used to making pottery, and who followed conventions in the 'recipe' and techniques of pot construction as well as in the shapes to be made.
The carinated forms range from broad, shallow bowls to deep-bellied bowls; one of the latter, from Auchategan, Argyll and Bute, is of classic Michelsberg 'tulip beaker' form while others would seem 'quite at home' in Chasseo-Michelsberg assemblages from northern France. Carinations are generally gentle, and in some cases the pots are S-profiled. The uncarinated forms comprise generally roughly hemispherical bowls and cups, and also large necked jars, with a deep-bellied, S-shaped profile. With all the pots, surfaces have been carefully smoothed, and in some cases the exterior (and sometimes interior) have been polished to a low to medium sheen, or even burnished to a high sheen. Lithic inclusions are sparse, often less than 3% in density, and often feature the use of crushed granitic stone, with tiny mica platelets giving the surface a slight glitter. Widespread technical details of manufacture include the marked thinning of the neck just above the carination, which is particularly prevalent on the wide shallow bowls; while this weakened the vessel - with many pots having broken at this point - it nevertheless helped in achieving the desired vessel shape. Once more, the widespread occurrence of this feature points strongly to CB pottery having been introduced by potters who shared the same ceramic tradition.
While some have accepted Andrew Herne's suggestion that carinated bowls had a special, ceremonial function, the evidence does not substantiate such a view. There is abundant evidence for the use of some carinated (and a few uncarinated) bowls for cooking, but they would also have been used for serving, and larger vessels for storage. This pottery has been found in the full range of contexts, from the domestic to funerary and other monuments.
The subsequent development of this tradition is, as indicated above, a story of regional diversification, with a process of style drift having operated in different ways, at different times, in different areas. In north-east Scotland, as Henshall had observed as long ago as 1983, a regional style emerged early on, featuring the increased use of fingertip fluting and of ripple-burnishing; the addition of lugs; and the addition of new forms, including baggy lugged bowls. This 'North East Carinated Bowl' (NECB) pottery finds echoes in the developed Carinated Bowl pottery of northern Ireland (in what Case called 'Lyles Hill ware: 1961), and this is no coincidence, as there are documented links between NE Scotland and NE Ireland, via the Great Glen (e.g. in the use of porcellanite axeheads from Co. Antrim). The early date at which this 'style drift' occurred is indicated by the assemblage from the so-called 'hall' at Balbridie, Aberdeenshire: built within a generation or so of the near-identical 'hall' at Warren Field, Crathes, just across the River Dee, its assemblage is of NECB pottery, whereas that at Crathes is 'traditional Carinated Bowl'. The Balbridie assemblage includes sherds from two sharply carinated bowls with decoration on their collars : these constitute the beginnings of what was to become the Unstan Bowl, and it is assumed that this represented innovation in pot design.
Other regional versions of 'developed Carinated Bowl' pottery include a general coarsening and thickening of the vessels, the occasional addition of lugs, and shape deviation from the earliest carinated forms.
In the west and south-west of Scotland, a fusion of the Breton and Carinated Bowl traditions can be seen, with decorated bipartite bowls occurring along with developed CB forms to constitute Scott's 'Beacharra' tradition, with its regional variability. Into this mix was added the use of deep baggy lugged bowls; as argued elsewhere (e.g. Sheridan 2004), this may well represent the adoption of a south-west English style of pottery (formerly known as 'Hembury Ware', thanks to north-south interactions within the Irish Sea area from the c 37th century. Some sharing of styles between NECB pottery and that found in W and SW Scotland is clear from the distinctive pots formerly known as 'Achnacree Bowls' (and as part of 'Rothesay Ware' ): these have long, vertical necks, heavy, hooked rims and shallow bellies, and are decorated with vertical lines of either ripple burnish or incision. Examples have been found at Culduthel , near Inverness, in a domestic context; in the passage tomb at Achnacree ; in the Clyde tomb at Nether Largie in the Kilmartin Glen ; and in Clyde tombs in Bute. The example at Culduthel comes from a context radiocarbon dated to c 3600-3500 BC and this provides a reasonable estimate of the date of this pottery.
A recent attempt to use Bayesian modelling to characterise the dating of modified Carinated Bowl pottery in Scotland has been made by Whittle et al. (2011), but this has failed to take into account that defining an end to this process is difficult, since ceramic traditions tend not to end abruptly; instead, we can trace a gradual process of style drift as conventions change and as new design ideas are adopted, through local innovation and through links with other areas. For this reason the use of Bayesian modelling is flawed. (See Sheridan 2012).
The spread of pottery using to the Outer Hebrides and the Northern Isles
It was this fusion of Carinated Bowl and Breton-origin pottery that spread to the Outer Hebrides, parts of western Scotland and north-west Scotland, probably during the late 38th or 37th century BC. Jack Scott (1966) has termed this pottery 'Hebridean Beacharra', and examples can be seen from sites such as Northton (Simpson et al. 2006), Calanais (Ashmore forthcoming), Eilean Domhnuill (Armit 2003) and various chamber tombs (Henshall 1972). The repertoire includes both undecorated and highly decorated vessel forms, in a variety of shapes. The former include simple uncarinated bowls, bowls with flanged rims and deep lugged jars (with their 'Hembury/South-Western pottery' affinities) and the latter include large ridged jars and Unstan Bowls - a type of vessel shared with Orkney and north-east/east Scotland, and almost certainly adopted in the Hebrides thanks to contacts with Orkney and/or the north-east mainland. Decoration is almost exclusively by incision. The dating of this 'Hebridean Neolithic pottery' tradition leaves much to be desired, with the existing dates suggesting an implausibly long currency from around the 37th century (or even possibly late 38th century) until the early third millennium. Improvement of the dating is a key research priority.
As far as the earliest Neolithic pottery in Orkney is concerned, this too contains an undecorated and a decorated component, with Unstan Bowls possibly being present from the beginning. Close ceramic links with the north-east mainland are in evidence, and it may be that the farming communities who pioneered farming in Orkney came from the north-east Mainland. The widespread use of the term 'Unstan Ware' offers a misleading impression of consistency among the pottery associated with Unstan Ware, and should be avoided. Key assemblages for understanding the early development of pottery include the Knap of Howar (Ritchie 1983) and Pool (Hunter 2007).
The earliest pottery in Shetland consists of a handful of very small, undecorated, slightly coarse sherds from West Voe. While these are too small to be diagnostic, they are most likely to resemble the plainware component of the ceramic tradition of the Hebrides and western mainland.