Close comparandum--overlap?

Current archaeological thinking is that two general pathways of Neolithic settlement existed in the British Isles.  Small Neolithic groups of settlers migrated into Britain and Ireland along both pathways over time, versus a large scale invasion.  It was a slow drip "replacement theory" via Neolithic technology, so to speak.   

One migration pathway moved up the Atlantic coast through the Irish Sea, both shores of which were settled--eastern Ireland and western Britain including Scotland.  These "Breton" Neolithic settlers originated in the Morbihan region of Brittany, now in present day France. 

Early Neolithic Cup and Ring marks at Achnabreck, Knapdale--April 17, 2019

 

Cairnbaan--April 17, 2019

Brittany in general, and Morbihan in particular, is noted for its world famous Carnac Stone alignments, over three thousand stones all told. One of the Scottish sites attributed to "Morbihan migrants" was Achnacreebeag.

   

Achnacreebeag lies near the head of Kilmartin Glen close to Cairnbaan's and Achnabreck's renowned Neolithic "rock art" which we visited in 2019 from our "base" in Campbeltown on the Kintyre peninsula.  Kilmartin Glen, of course, is a world heritage site, renowned for its own concentration of Neolithic cairns, standing stones and stone circles.

 

Brittany's Neolithization on the continent began sometime after 5000 BC, and perhaps as late as 4500 BC--many centuries before the Neolithic migration from Brittany into the west of Britain.  In Brittany, the Neolithic period is characterized by "rock art"--circular spirals and cup marks.  It is no surprise that this rock art would essentially be mirrored in Scotland's west at "associated" sites like those at Cairnbaan and Achnabreck in Knapdale, Scotland.    

"Neolithic Breton Migration"; image ScARF

As for dating, a few Carnac monuments are said to be as early as 4500 BC.  If true, those Breton monuments would have been built by some of western Europe's last Mesolithic Hunter-Gatherers, or rather at the time of the metamorphosis from hunter-gatherer to agriculturist.  The majority of Carnac stones in Brittany, however, are widely thought to have been built about 3300 BC...which was well before Stonehenge, but a couple centuries after many Orkney monuments were constructed. 

Late Castellic; Scottish Archaeological Research Framework

A previous post noted 3300 BC as the approximate date the Orkney vole was introduced in Scotland's north isles by Neolithic trade via the second (Flanders) migrant pathway.  

Pottery styles differed by the Neolithic people moving on both paths.  The Neolithic "Breton" migration to the British Isles via the Irish Sea brought their pottery--called Morbihan pottery style, or sometimes Late Castellic.  The style, shown in the photo of the Achnacreebeag bowl (image credit to ScARF), apparently has dating technique "issues".  Presently, it can only be comparatively dated, i.e. based on similar finds in Brittany--c. 4300 BC - 3900 BC.  But this "date bracket" is most likely when British and Irish monuments and their pottery were created by the Breton migrants, with 3900 BC being the most probable.

"Neolithic Flanders Migration; ScARF

A second migration route existed as well.  It was the pathway by which the Orkney vole found a new home.  This pathway originated in Flanders (Belgium and north France) and settled the south and east of Britain, and directly settled Orkney from the sea.  The Flanders culture was Late Michelsberg or a close successor.  The famed "Unstan Ware" of Orkney (found at Unstan Cairn and Knap of Howar) is now known as Carinated Bowl pottery--the CB Culture.  

A large amount of this pottery type was uncovered at Unstan Cairn on Mainland Orkney.  Hence its name.  This geographically specific place name is now considered limited--exclusive of others.  So the term "CB pottery" is more appropriate, permitting inclusion of a wider assemblage of related groups across an expanded area. 

The purpose of rebranding Unstan Ware is not political correctness nor a slight to Orkney.  Carinated Bowl culture more accurately reflects Neolithic "social" interactions for the time.

CB sites in Argyll and Ireland also exist.  Here, pottery tells the tale of an "internal" migration by the CB culture into the "neighboring" Breton pathway sites along the Atlantic facade of west Scotland.  These CB sites are thought to have been fairly rapidly settled from the Neolithic settlements that had been established in east Scotland by the Flanders pathway rather than directly from the continent. 

Lady's Bridge over River Ness, Inverness--April 9, 2022

The Neolithic CB culture apparently used Scotland's Great Glen Rift with its world famous Loch Ness as an "inter-expressway" through the Highlands to found CB sites in a region initially settled by the Morbihan-syle culture.  See:  "Neolithic Flanders Migration" diagram from ScARF (Scottish Archaeological Research Framework).   

Carinated Bowl pottery is now considered one of several variants of Chasseo-Michelsberg pottery from Flanders, c. 4000 BC.  This tentatively (or tenuously) links the Michelsburg Spiennes flint miners and their industrial scale tool production by way of extensive trade routes to east Scotland and Orkney.  

The CB culture moving into west Scotland was contemporary with the Morbihan-style pottery sites already in Ireland and Argyll.  These two pottery styles, in their initial form in the British Isles, are said to not overlap.  Others more expert can decide whether variants constitute "overlap" of the two Neolithic migrant potteries.  I defer with an admission that is too expert a distinction for me.

Morbihan variant style(?)  Islay Museum--April 2, 2018

Generally speaking, the Morbihan-style pottery was limited to the west, to Neolithic sites that sprang from the Irish Sea migrant pathway.  The CB style from the Flanders pathway, had a greater distribution in Britain.  "Cross cultural" exchanges occurred.  Indeed, they could have hardly been avoided.  

It should be noted that pottery use itself (which almost defines Neolithization) was not uniformly and immediately taken up in the whole of the British Isles.  Some areas--Outer Hebrides and some of the Inner Hebrides, some Northern Isles and parts of remote west Scotland and Sutherland--did not take up pottery use as late as c. 3600 - 3500 00 BC.

Skara Brae, Mainland Orkney April 12, 2022

Local variants of Late Castellic and Carinated Bowl are said to exist, as potters shared ideas.  A new "British" form (evidently beginning in Orkney versus being introduced from the continent), became predominant.  This flat bottomed Grooved Ware was introduced and relatively quickly taken up.  It remained in Britain Neolithic use many centuries after it fell from favor elsewhere.

Apparently the Grooved Ware tradition lacks clear "evolutionary" evidence.  Thus, it is thought that perhaps Grooved Ware sprang from a conscious decision to design a new and different pottery style.  Flat bottoms permit setting the pottery  on a rock shelf in all those "new build" Neolithic houses with built in shelves like at Skara Brae, versus pottery with a rounded conical base more useful for placing on campfire coals.  Grooved Ware became the British Neolithic innovative and "fashionable" pottery.  "What will they think of next?!"  Wheels, apparently.