For the centuries following this initial, dual appearance of pottery, two main processes can be discerned: firstly, the emergence of regionally-divergent trajectories – albeit with elements of inter-regional design sharing that echo other evidence for inter-regional exchange – and secondly, a geographical expansion in the use of
Figure 2. Examples of ‘traditional Carinated Bowl’ pottery from various sites in Scotland, and map indicating the hypothetical route taken by immigrant farming groups from the northernmost part of France and their descendants. Based on Sheridan 2007 and 2010a, with additions and amendments
pottery that encompassed (inter alia) the Northern and Western Isles. The latter seems to have taken place after the former had begun, and this – along with a continuation of the regional ‘style drift’ – accounts for the differences between the Early Neolithic pottery of those archipelagos.
Space does not permit an exhaustive description of all of the regionally-specific ways in which the ceramic repertoire changed; some idea of this is given in the aforementioned ScARF web resource, and a discussion of the sequence in Shetland has recently been published (Sheridan 2014a; cf Sheridan 2003 for west and south- west Scotland). Suffice it to note the following key aspects:
• The process of ‘style drift’ in the manufacture of Carinated Bowl (CB) pottery started very early in north-east Scotland, as is clear from a comparison of dates for ‘traditional’ CB pottery with those for the ‘modified CB’ pottery of Henshall’s ‘North East style’ (1983a) – in particular from Balbridie (Whittle et al 2011, 824-8, 832-3). This is all the more striking given the spatial, as well as chronological proximity of the large house (‘hall’) at Balbridie to its counterpart just across the Dee at Warren Field, Crathes, where an assemblage of traditional CB pottery was found (Sheridan 2009a).
• As noted above, the nature and tempo of the ‘traditional’ to ‘modified’ CB style drift varied from region to region and over time. Trevor Cowie’s review of developments in east-central Scotland (Cowie 1993a), for example, highlighted the shift there to thicker-walled and generally coarser vessels, with heavier rims and occasional lugs, while in north-east Scotland the novelties include elements of what was later to become the Orcadian ceramic repertoire. In particular, the genesis of the ‘Unstan Bowl’ – a bipartite bowl with an upright, straight, decorated, collar-like neck – can be traced back to the 38th century BC assemblage at Balbridie, where the vessels in question stand out as examples of local design innovation (Ralston 1982). Figure 3 offers a ceramic ‘family tree’ for this particular and distinctive vessel type. Another of the elements of the Orcadian repertoire that had its origins in the modified CB pottery of north-east Scotland is the undecorated bipartite bowl with a vertical or near-vertical neck, heavy rim and well-defined carination, as seen for example at Urquhart, Moray (Henshall 1983a, fig 5.3).
• Other examples of the CB tradition style drift that transgress regional boundaries – and which complement other evidence for inter-regional contact, for example the distribution of Antrim porcellanite stone axeheads (Sheridan
Figure 3 (next page). The ‘Unstan Bowl’ and its origins in the ‘North-East’ style of modified Carinated Bowl pottery. 1 Balbridie, Aberdeenshire; 2 Spurryhillock, Aberdeenshire; 3 Culduthel, Highland (Inverness-shire); 4 Urquhart, Moray; 5 Grandtully, Perth and Kinross; 6 Garrywhin, Highland (Caithness); 7 Ord North, Highland (Sutherland); 8 Eilean Dòmhnuill, Loch Olabhat, North Uist; 9 Allt Chrisal, Barra; 10-16 Orkney: 10 Taversoe Tuick, Rousay; 11 Midhowe, Rousay; 12 Rowiegar, Rousay; 13 Knap of Howar, Papa Westray; 14 Blackhammer, Rousay; 15 Isbister, South Ronaldsay; 16 Unstan, Mainland. Sources: 1 Ian Ralston; 2 Alexander 1997; 3 Headland Archaeology; 4 Henshall 1983a; 5 Simpson & Coles 1990; 6 Davidson & Henshall 1991; 7 Henshall & Ritchie 1995; 8 National Museums Scotland; 9 Branigan & Foster 1995; 10-12, 14-16 Davidson & Henshall 1989; 13 Ritchie 1983
1986) and of Arran pitchstone (Ballin 2009; 2015) – include the extensive use of fingertip fluting (a minor element in the traditional CB repertoire) and its glossier version, ripple burnishing, on carinated bowls. This is a feature of modified CB pottery that extends from north-east Scotland to east-central Scotland, south-west Scotland and northern Ireland (eg at Lyles Hill, County Antrim: Sheridan 1995); within Ireland its period of use included the late 38th/early 37th century ‘house boom’ (Smyth 2014). A particularly clear example of this inter-regional design sharing can be seen in the distinctively- shaped, low-carinated bowls with long straight upright necks, heavy rims and extensive fluting (or, in some cases, grooving) that Henshall termed ‘Achnacree Bowls’ (Fig 4; Henshall 1972, 100-2). An example from Culduthel, on the outskirts of Inverness (Sheridan 2010b), offers a striking match for others at the opposite end of the Great Glen and beyond, in Argyll and Bute: at the passage tomb of Achnacree, for example (Henshall 1972, 303); in the Clyde cairns at Geirisclett, North Uist (Dunwell et al 2003), Nether Largie in Kilmartin Glen and Glenvoidean on Bute (Henshall 1972, 302, 306); and
Figure 4. A specific vessel type within the modified Carinated Bowl repertoire, demonstrating inter-regional sharing of design ideas: the ‘Achnacree Bowl’. 1 Culduthel, Highland; 2 Geirisclett, North Uist; 3-7: Argyll and Bute: 3 Achnacree; 4 Nether Largie; 5 Balloch Hill; 6 Glenvoidean; 7 Townhead. Sources: 1 Headland Archaeology; 2 Dunwell et al 2003; 3,4,6 Henshall 1972; 5 Yarrington 1982; 7 Scott 1977
at settlements at Rothesay on Bute (Scott 1977) and at Balloch Hill on the Kintyre peninsula (Yarrington 1982). The Culduthel example is from a context radiocarbon-dated to 4870±30 BP (SUERC-17222, 3640-3520 cal BC at 95.4% probability: Ross Murray, pers comm).
• The regionally-specific ceramic trajectories seen in western and south-west Scotland demonstrate not only the process of style drift in the CB tradition (including this sharing of design elements with north-east Scotland), but also a continuation in the use of Late Castellic-style pottery and the adoption of design elements from further afield, probably including south-west England, during the first half of the fourth millennium (Sheridan 2003, fig 2.5). As noted above (and in Sheridan 1995), the repertoire also reflects design sharing with north-east Ireland. The fact that the distinctive decorated bipartite bowls of unmistakable Late Castellic ancestry (Fig 5) are found alongside modified CB pottery in Clyde cairns – including at the recently-excavated monument at Blasthill on the Kintyre peninsula (Cummings & Robinson 2015, illus 5, pot 1) – implies that the descendants of the two sets of original immigrant farming groups to colonise this part of Scotland cohabited happily, their ceramic repertoire acknowledging this duality of origins. (It is assumed that the population mix also included the descendants of the indigenous – and non-pottery-using – communities of hunters, gatherers and fishers who seem
Figure 5. Ceramic ‘family tree’ for closed bipartite bowls featuring a ‘rainbow’ motif, with or without a fringe: 1 Early Castellic (c 4700/4600-4300 BC), from Castellic, Morbihan, Brittany; 2-4 Late Castellic (c 4300-3900 BC): 2 Er Grah, Morbihan; 3 Vierville, Normandy; 4 Achnacreebeag, Argyll and Bute; 5-8 Early Neolithic examples from Clyde Cairns and from a related type of monument in Northern Ireland: 5 Ballymacaldrack, County Antrim, Northern Ireland; 6 Blasthill, Argyll and Bute; 7-8 Beacharra, Argyll and Bute. For further developments in this ceramic ‘family tree’ in Ireland, see Sheridan 1995, fig 2.3. Sources: 1-4 after Sheridan 2010a (where original sources cited); 5 Collins 1976; 6 Thompson & Peterson 2015; 7-8 Henshall 1972
to have acculturated.) The presence of the same mixture of Breton-derived and modified CB tradition pottery in court and portal tombs in north-east Ireland – where the decorated bipartite bowls had previously been labelled ‘Ballyalton bowls’ (Sheridan 1995, fig 2.3) – reflects the intensity and regularity of contacts across the north channel of the Irish Sea at this time. The elements of the ceramic repertoire in western and south-west Scotland, and north-east Ireland, that find their closest match in ‘Hembury ware’ (also known as ‘South-western style’ Early Neolithic pottery) in south-west England include deep baggy lugged jars (Sheridan 2004a, fig 2.5). These jars differ from the lugged jars of the north-east Scottish modified CB repertoire (eg at Leggatsden Quarry, Aberdeenshire: Henshall 1983a, fig 6.10) in having ledge- like, rather than knob-shaped, lugs. Such long-distance connections up and down – as well as across – the Irish Sea should not surprise us, given all the other evidence that exists to show that the establishment and maintenance of networks of contacts was important to these early farming communities (Sheridan 2003; 2004a; 2010a).
As for the other major development mentioned above – the spread of pottery-using to the Western and Northern Isles – this is likely to have been part of a more general expansion of farming groups as these communities flourished, grew and decided to colonise other areas. The currently-available evidence from monument types, pottery and other material culture suggests that the Outer Hebrides were colonised from those parts of western and south- west Scotland where both Clyde cairns and passage tombs were being built,1
while Orkney’s first farmers are most likely to have come from the north-east Scottish mainland, probably Caithness, and Shetland’s first farmers are most likely to have come from western Scotland. The episodes of expansion will have been independent of each other, but the underlying reason is likely to have been population growth allied with a willingness, desire or perceived necessity to colonise new areas.
All these expansions are likely to have occurred during the second quarter of the fourth millennium, although the date and duration of the process requires further clarification. As argued elsewhere (Sheridan 2014a, 69), the arrival of pottery- using farmers in Shetland could have occurred as early as the late 38th or 37th century BC. The earliest pottery in Shetland consists of just four featureless sherds found at West Voe, and beyond noting that they lack any obvious diagnostic features of the CB tradition there is little that can be said about them, other than that their forerunners are likely to have been made in western Scotland, in view of the similarities in passage tomb types between that part of Scotland and Shetland (ibid, 69-70 and fig 1).
Regarding the expansion to the Outer Hebrides from western/south-west Scotland, there is an increasing number of radiocarbon dates – including several deriving directly from encrusted organic residues on Hebridean incised vessels (Sheridan et al 2014) – confirming that pottery use had been established in the
1 It is currently unclear whether the earlier, ‘Atlantic façade’ strand of initial Neolithisation had extended as far as the Outer Hebrides.