Scotland’s First Settlers

Section 5

The archive version of the text can be obtained from the project archive on the Archaeology Data Service (ADS) website, after agreeing to their terms and conditions: ads.ahds.ac.uk/catalogue/resources.html?sfs_ba_2007 > Downloads > Documents > Final Reports. From here you can download the file ‘Wickham-Jones,_Lithic_Raw_Materials_Around_the_Inner_Sound.pdf’.

5.1 Introduction

Scotland’s First Settlers has identified several different raw materials that were used for flaked stone tools in prehistory in the area (see Illustration 365, right; Tables 176 & 177, both below). At first it was hoped to enlist the help of specialised geologists to recognise these definitively and provide more information on their occurrence and archaeological development. In the event, this was not possible, partly because of a lack of funding and partly because the archaeological queries are, in geological terms, very specialised so that it was difficult to find points of agreement between the geologists consulted. SFS consulted some half a dozen geologists and found that they offered differing views, for example as to the differentiation of flint or chert from other chalcedonic silicas, or the recognition of baked mudstone as apart from baked volcanic tuffs. (From top left: Rùm bloodstone×2, baked mudstone×2, quartz×3, with chalcedonic silica×2 in the centre). Skip Tables.

Table 176
Chalcedonic Silica: including flint, chert, agate and jasper Baked Mudstone Rùm Bloodstone Quartz, Quartzite and Rock crystal Coarse stone: including a variety of sandstones

Table 176: Different types of raw material identified by the project

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Table 177
Site Name	Baked Mudstone	Chalcedonic Silicas	Rùm Bloodstone	Quartz and Quartzite	Coarse stone	Flint	Other	Total	Location*
SFS 185 Achintee		1	2					3	SLS
SFS 95 Achnahannait Bay	1	3						4	W
SFS 68 Allt na Criche		12		47				59	E
SFS 10 Allt na h’Uamha	1	6		1	1			9	SLS
SFS 60 Allt-na-h-Eirigh		1						1	E
SFS 150 Alt Cadh an Eas		2		2				4	SLS
SFS 29 An Corran B	34	41		1				76	W
SFS 30 An Corran C	299	217		12			1v	529	W
SFS 31 An Corran D	10	45	1	2				58	W
SFS 101 An Corran E	249	284	5	17				555	W
SFS 193 An Corran F	8	18						26	W
SFS 194 An Corran G		3						3	W
SFS 1 An Corran, Meso site		1						1	W
SFS 116 Applecross Mains Shovel Pits		7		3				10	E
SFS 75 Applecross Manse		28	17	52				97	E
SFS 66 Ard Clais Salacher 2		5		2		5		12	E
SFS 102 Ardheslaig 1			1					1	E
SFS 6 Ashaig 1	2			1				3	S
SFS 92 Ashaig 3		6	1	1				8	S
SFS 93 Ashaig 4		2		1				3	S
SFS 32 Brogaig	52	47		3				102	W
SFS 168 Camas an Leim		1						1	SLS
SFS 188 Camas an Leim		4						4	SLS
SFS 71 Camusteel 1				1				1	E
SFS 77 Camusteel 2		5						5	E
SFS 17 Church Cave		2		2				4	C
SFS 61 Clachan Church				2		1		3	E
SFS 99 Clachan Church Midden		1						1	E
SFS 147 Cnoc na Celpeirein		9		27			1v	37	SLS
SFS 89 Coire Sgamadail 1	1	3		3				7	E
SFS 90 Coire Sgamadail 3–6		8						8	E
SFS 49 Creag na-h-uamha		2						2	E
SFS 2 Crowlin 1	1	25		4		1		31	C
SFS 22 Crowlin 3		53		5		2		60	C
SFS 23 Crowlin 4									C
SFS 26 Crowlin 7		4						4	C
SFS 188/190 Diabeg				1				1	SLS
SFS 152 Doire na Guaile, Rona	3			76	1			80	C
SFS 117 Dun Hasan 2	1	2						3	W
SFS 104 Fearnmore 1	115	131	40	468				754	E
SFS 80 Fearnmore 2				1				1	E
SFS 114 Fergus’ Shelter		68		12	1			81	E
SFS 8 Loch a Sguirr	60	27		62				149	C
SFS 18 Loch a Sguirr 2				5				5	C
SFS 171 Meall na h’Airde 2		23		4				27	SLS
SFS 96 Meallabhan	2	20		1	1			24	E
SFS 183 Nead an Eoin		3	5	3				11	SLS
SFS 50 Pabay 1		9	1	4				14	C
SFS 94 Port Earlish	1	5						6	W
SFS 9 Redpoint	30 (197)	32 (35)	34 (37)	751 (1087)				847 (1356)	SLS
SFS 57 Rubha a Ghair		6	1	6				13	E
SFS 58 Rubha Chuaig		1			1			2	E
SFS 44 Rubha’an Droma Bhain, Scalpay	1	2						3	W
SFS 71 Sand 5		1						1	E
SFS 12 Scalpay 2		16	11	29				56	Scalpay
SFS 33 Scalpay 3		59	10	82			1v	152	Scalpay
SFS 56 Scalpay 4		5	1	20				26	Scalpay
SFS 118 Scalpay 5		36	18	148				202	Scalpay
SFS 198 Scalpay 6a	3	314	16	323	1		2v	659	Scalpay
SFS 195 Scalpay 6b		55	3	1520				1578	Scalpay
SFS 196 Scalpay 7		6	2	22				30	Scalpay
SFS 197 Scalpay 8		1	1					2	Scalpay
SFS 15 Sheildaig	1	14 (663)	1 (68)	29 (5270)				45 (6001)	SLS
SFS 141 R 1/25		2						2	C
SFS 36 Staffin Island	1	6						7	W
SFS 191 Suarbie Burn		7						7	W
SFS 162 Teanga Fhiadhaich		1	1	11				13	SLS
SFS 186 Torridon Mains		2		1				3	SLS
SFS 20 Toscaig 2		3		1				4	E
SFS 34 Toscaig 3		4		1				5	E
SFS 39 Toscaig 7		2		2				4	E
SFS 41 Toscaig 9	7							7	E
SFS 105 Uags	1	2		7				10	E
SFS 61 Uamh an Traill				1				1	W

Table 177: SFS survey sites: lithic raw materials used, other – (u = unknown, v = volcanic glass); Back to Section 5.8;
Key * = location in the Inner Sound: E = eastern coast; W = western coast; C = central islands; S = southern coasts; SLS = Lochs Carron and Torridon

5.2 Method

As a part of the project major sources of raw materials were visited and the surveyors collected and recorded any nodule material that they found (see Appendix 13). In addition, walks were made across some of the beaches in the study area in order to look for nodules of suitable materials, but little was found (see below).

It soon became clear that detailed work on the lithic raw materials would involve the individual classification of every archaeological piece by a specialist and thus be lengthy and expensive, even once an appropriate specialist had been found. In the event, basic differentiation was done by eye by the author, and the discussion is written on this basis. This obviously leaves scope for more precise geological work to be done in the future. The analysis of the use of lithic raw materials around the Inner Sound has much to offer the wider picture of prehistoric activity in the area and it would be good to see it developed.

The problems facing the basic differentiation of the lithic raw materials in use around the Inner Sound are compounded by the ways in which different raw materials react while buried. Work undertaken as part of the Rùm project (Finlayson & Durant 1990) showed that both Rùm bloodstone and local flints were subject to surface alteration while buried so that they often (but not always) ended up a uniform grey colour that made it impossible to distinguish between the two. We do not know whether this alteration extends to other chalcedonic silicas, or the baked mudstones, but it means that accurate identification of the different raw materials is impossible without further analysis of processes such as surface alteration. Furthermore, Finlayson’s work for the Rùm project highlighted the considerable changes that come about as a result of burning (whether accidental or deliberate) so that this, too, must be taken into account (Finlayson 1990b).

The following discussion should, thus, be read with the caveat that the picture may change when more detailed work can be done. It does, however, provide a list of the different types of raw material exploited, a rough idea of their varying quantities across the Inner Sound, and an initial interpretation of lithic raw material use in archaeological terms. For that reason it has been included in the overall report.

Throughout this section a distinction is made between primary sources, that is locations where a lithic raw material is found in situ in the rock, and secondary sources, or locations where nodules of a particular raw material have eroded out of their parent rock and are to be found as a component of beach or river gravels, loose on the ground surface, or in deposits of glacial till.

5.3 Chalcedonic Silica: including Flint, Chert, Agate and Jasper

Flint is one of the most commonly used materials for stone tools in prehistoric Britain, but as elsewhere in Scotland (Wickham-Jones 1986) it did not dominate the lithic assemblages of the Inner Sound. The main reason for that lies in its relative scarcity. Flint is a non-clastic siliceous sedimentary rock, part of a group known overall as chert (Hallsworth & Knox 1999:22), of which other forms are chert itself, agate and jasper, all of which have been identified among the archaeological assemblages of the Inner Sound. All of these stones occur naturally, in different amounts, around the Inner Sound. They can be difficult to distinguish with the naked eye, and are classified collectively as chalcedonic silica in this report. There is one exception to this, and that concerns the sites with more recent activity where gunflints were found: gunflints tend to be of grey, often imported, flint, and they have been classified as flint.

Flint and chert pebbles occur both in sedimentary rocks, such as the Durness Limestones (Robertson ed 1994), and in gravel and till deposits, whether of glacial, marine, or riverine origin. As such they are to be found both in beach and river gravels around the Inner Sound, and in till deposits, for example along the Suarbie Burn in Staffin (see Illustration 270, right). Chalcedonic silicas are particularly abundant around Staffin Bay both on the beach and in till, but they may also be found elsewhere. The abundance of material at Staffin means that Staffin is likely to have acted as an important source of chalcedonic silica for those who lived around the shores of the Inner Sound in prehistory. Initially, it was hoped that it might be possible to differentiate between the silicas from Staffin and those from elsewhere, but that has not been possible so that it is impossible to quantify the importance of Staffin as a source of chalcedonic silica, except to say that it must have formed one of the main sources around the Inner Sound.

In general, chalcedonic silicas have fairly uniform knapping qualities though stone from different sources can have different inclusions which affect the knapper, and some of them are much tougher, and thus require much more force to fracture, than others.

5.4 Baked mudstone

Mudstones are fine grained sedimentary rocks. There are many different types of mudstone (Hallsworth & Knox 1999), some of which occur in Skye (Hesselbo & Coe 2000). In some cases contact with igneous activity means that they have been baked hard to form small rafts of material (identified by some as porcellanite) that is suitable for knapping. Deposits of baked mudstone are small and hard to find and in many cases they are too small to signify in the geological memoirs, but known deposits do occur in Staffin. Baked mudstone from Staffin comprises two types: in situ material in small rafts in the cliffs at An Corran (see Illustration 101, right); and eroded nodules such as pebbles on the beaches below. It is likely that other deposits exist in Skye, and there may well be others elsewhere: Good enough notes deposits in the Shiant Isles (1999). The deposits at An Corran were, however, the only baked mudstone source around the Inner Sound to be found and visited by the project. Unfortunately these outcrops were disturbed by rock blasting in the late 1990s so that examination of possible prehistoric extraction is now impossible.

While it is possible that other sources were being exploited in prehistory, the lack of obvious material elsewhere means that the source at An Corran is likely to have formed the major, and possibly exclusive, source of baked mudstone for the Inner Sound in prehistory. The importance of this source is emphasised by the presence in Staffin Bay of a concentration of archaeological activity that is unparalleled, in terms of quantity, elsewhere around the Inner Sound. The site at An Corran itself provides evidence of activity from the seventh millennium BC to the second millennium BC (Hardy et al forthcoming a), while SFS survey work has revealed a series of lithic scatter sites around Staffin Bay which, though undated, provide evidence for prolific prehistoric activity. Staffin Bay was obviously important in prehistory and it would have offered many resources. It would seem that one resource here was abundant lithic raw material: both in pebble form on the beach and as outcrops of baked mudstone in the cliffs above An Corran. The presence of chalcedonic silica in the area (above) can only have added to its attractions.

Baked mudstone is fairly easy to knap when fresh, with a fine fracture that does not generally require too much force. It can be brittle, however, with friable edges that are not always well suited to heavier tasks. Some mudstones can be harder to work, and require more force to remove flakes and shape tools. As it degrades mudstone breaks more easily.

It is worth noting that some igneous materials, such as tuff and basalt can appear very similar to the local baked mudstones and may well have been included under the heading ‘baked mudstone’. It is likely that all were collected in the same general area.

5.5 Rùm bloodstone

Rùm bloodstone is a crypto-crystalline silica which occurs in association with lavas of Tertiary age. Several sources of bloodstone are known in the west of Scotland (Durant et al 1990), but work in the 1980s (Clarke & Griffiths 1990) indicated that the island of Rùm was the only source of knappable raw material in prehistory. Although there are in situ outcrops of Rùm bloodstone at the top of Bloodstone Hill (see Illustration 367, right), the evidence suggests that prehistoric knappers exploited nodules from the extensive scree deposits below (Wickham-Jones 1990). Rùm bloodstone was used, though often in small quantity, right around the Inner Sound, suggesting that contact, and transport, took place as much as 40km to the south. The implications of this are discussed below (Sections 5.7 and 5.8).

Work on surface alteration in the 1980s (Finlayson & Durant 1990) indicated that, once buried, artefacts of Rùm bloodstone undergo similar alteration to chalcedonies such as flint and chert. All can end up a uniform grey colour and it is very difficult to distinguish between them. Consequently, the amounts of Rùm bloodstone in individual assemblages may have been underestimated.

Rùm bloodstone is generally quite hard to knap, requiring a lot of force to detach flakes. Only a few nodules are siliceous, or ‘glassy’ enough to flake easily. Nodules also tend to contain inclusions which affect their fracture.

5.6 Quartz, Quartzite and Rock Crystal

Quartz is a crystalline siliceous mineral that forms a common constituent of many rocks. In its more granular form it is known as quartzite. Some forms of quartz are relatively homogenous and may be knapped for controlled tool production with ease, others are of less good quality and make more irregular tools. Quartzite is similarly variable in quality. Quartz and quartzite are common components of the rocks of the Inner Sound, and they occur both in situ (for example vein quartz) and as nodules which may be collected across the area in beach and other gravels as well as in local soils.

Quartz was a common constituent of the lithic assemblages around the Inner Sound and an important lithic resource in prehistory. The quality of quartz used at individual sites varied considerably, suggesting that it was collected locally. Quartzite is a less common component of the lithic assemblages, apparently used only to supplement other materials on occasion.

The variability of quartz has led to problems for lithic analysts in the past. Apart from anything else, the knapping characteristics on struck quartz cannot be read in quite the same way as flint, nor can they necessarily be regarded as analogous from one quartz area to another. Nevertheless, worked quartz has been considered as a component of many assemblages especially in north and west Scotland and it is currently the subject of a specialist study (Saville & Ballin 2000). Quartz flaking formed an important part of the prehistoric lithic repertoire in many other countries, especially in northern Europe where the literature is also of great relevance for those trying to make sense of worked quartz in prehistoric Scotland (for example Broadbent 1979; Knutsson 1988).

Rock crystal is a pure form of quartz which may be found occasionally around the Inner Sound and occurs in a few assemblages. It was not a common raw material.

5.7 Coarse stone

A variety of sandstones were also flaked on several sites, though they were never a major resource. Sandstone is to be found around the Inner Sound, usually as water-worn cobbles in beach and river gravels, and they are likely to have been collected in the vicinity of the individual sites. Cobbles were used to make tools of different kinds (Clarke, Section 3.6) and there is evidence that sandstone was also flaked. It may be that people started to flake it when they saw how it sometimes spalled during use. Generally, the sandstone would be too coarse and friable to make or hold good edges so that it was not an important flaking material, but its presence should not be overlooked.

5.8 Raw material use at the different sites

The most commonly used raw materials in the eighth millennium BC at Sand were baked mudstone and quartz (see Table 178, below). It is likely that the baked mudstone came from Staffin, across the Inner Sound, while the Rùm bloodstone must have come from the island of Rùm to the south. Some of the chalcedonic silica may also have come from Staffin, but the rest, including the other materials is likely to be local. The use of the different raw materials at Sand, including any selection for specific artefacts, is considered in detail under the discussion of the site at Sand as a whole.

Table 178
Sand Material	Quantity
Total	14,801
Baked Mudstone	5764
Chalcedonic Silicas	2532
Coarse Stone	100
Quartz and Quartzite	5343
Rùm Bloodstone	1059
Unknown	3

Table 178: Lithic raw material use at Sand

With regard to raw material use across the Inner Sound (see Table 177, above), the assemblage from Sand has been kept separate from the rest to avoid any skewing that might be introduced because of the use of different collection techniques, such as fine excavation and sieving, on site. In addition it has to be remembered that many of the other sites are undated, and those that have dates vary considerably in period (Section 4). As the dating evidence is so variable, the discussion of any possible chronological implications has been left for the final, general, section (below, Section 5.10). As the south coasts of the Inner Sound produced only three sites, each with very small lithic assemblages (a total of 14 pieces), they have not been considered. Scalpay was, however, looked at separately as detailed collection there yielded nearly 3,000 flaked lithics.

The use of the different raw materials around the Inner Sound is not uniform (see Illustration 532, below). The picture for the west side of the Inner Sound is heavily influenced by the assemblages from Staffin (An Corran A–E and Brogaig), which form the principal assemblages on that coast. Baked mudstone and chalcedonic silica were the most heavily used resources, which no doubt reflects the abundance of those materials at Staffin itself. Rùm bloodstone occurred in only very small quantity, and there was a small amount of quartz and quartzite. The east side is quite different. Baked mudstone was of much less importance among the survey sites, though the use of chalcedonic silica was still significant. There was some use of Rùm bloodstone, but by far the most common raw material was quartz and quartzite. These are likely to be local stones, and given the relative lack of imported material such as baked mudstone, and bloodstone, it is likely that the chalcedonic silica was also predominantly local. Skip Charts.

Interestingly, the assemblage from Sand does show notable differences to the other east coast sites. Baked mudstone was more important here, and chalcedonic silica and quartz relatively less so. The proportion of Rùm bloodstone was about the same. It is impossible to say at present whether these differences are the result of the finer excavation techniques in use at Sand as opposed to the survey sites, or whether they reflect a difference that may be due more to other factors such as chronology. Certainly most of the survey sites that have been dated do have more recent dates (Section 4) but more excavation on other sites would be needed to understand fully what is happening here (and see below).

The assemblages from the central islands of the Inner Sound are remarkably like those from the eastern coasts. They are dominated by quartz and quartzites, and baked mudstone is of less importance, perhaps surprisingly so given the apparently proximity of Staffin Bay. Rùm bloodstone was also little used, but chalcedonic silica was important. The lack of baked mudstone suggests that the chalcedonic silica in use came from local sources, or from naturally transported nodules that could be picked up on the beaches. Raw material use in Scalpay is notable because of the almost complete absence of baked mudstone despite the proximity of Scalpay to the source at Staffin. The lithic raw materials used here bear more resemblance to those of the central islands with a dominance of quartz and some use of chalcedonic silica. Rùm bloodstone is present in the Scalpay assemblages, but not in great quantity.

Lochs Torridon and Carron, the Sea Loch survey area, present yet another view. Here quartz and quartzite dominated the lithic assemblages, almost to the exclusion of everything else. There was very little baked mudstone and bloodstone, and only slightly more chalcedonic silica. This is likely to be a reflection of local geology.

5.9 Raw material use for different artefacts

Breakdowns of the different components of the assemblage at Sand largely reflect the characteristics of the various raw materials (see Illustrations 533, above & 534, below), suggesting that there was little conscious selection by material on the part of the knappers. Thus, though there are far more blades of baked mudstone than one might expect, and though both regular flakes and retouched pieces are more common in this material, it is difficult to tell whether this reflects the more regular flaking characteristics of baked mudstone which would lead to more of this sort of piece, or whether it is a conscious selection on the part of the knappers. Perhaps it is a bit of both. Interestingly, however, microliths, which might also be thought to need a more regular material because they are based on blades, make less use of baked mudstone, though it still predominates for their manufacture. Both Rùm bloodstone and chalcedonic silica were apparently quite suitable for the manufacture of microliths. Quartz, while making up about one third of the assemblage, was of less use for blades, regular flakes and retouched pieces and this no doubt reflects the friable nature of much of the local quartz. Skip Charts.

Away from Sand, the small sizes of most of the assemblages and variable collection techniques (which have introduced their own biases) make it difficult to extract meaningful information on the differential use of raw materials. Retouched pieces are almost all of chalcedonic silica, except for one or two baked mudstone pieces – all from the Staffin sites, and one microlith of Rùm bloodstone from Fearnmore 1 at the north end of the Applecross peninsula. The general make-up of individual components of the assemblages very much mimics the breakdown of raw materials used at the different sites, except that on the east coast and Sea Loch sites the proportion of regular flakes of baked mudstone is higher than might be expected. At Redpoint quartz was used successfully to make blades, while at Fearnmore 1 there are few blades anyway and they are of baked mudstone (two) and chalcedonic silica (one).

5.10 General discussion

The four main lithic resources used around the Inner Sound have properties that vary considerably. Not only are they not of equal merit with regard to ease of fracture, they also provided working edges of different durability. Tool manufacture, tool use, and tool maintenance thus vary both between materials and chronologically, as fashions and tasks changed with time.

Quartz was the least reliable, though it provided the most easily available material for the sites in the east and central island belt. Assemblages such as that from Shieldaig show that quartz could be worked very successfully though it resulted in a considerable amount of debitage. Baked mudstone, Rùm bloodstone and chalcedonic silica are all more predictable stones. Baked mudstone tends to be quite brittle and work relatively easily, though it can vary greatly depending on its original location in relation to the heat source, and it tends also to degrade more rapidly. Rùm bloodstone can be a tough stone to work as can chalcedonic silica though some of the chalcedonies were more brittle and thus easier. The knappers around the Inner Sound were quite aware of these individual characteristics and they adapted their knapping techniques in order to make the best use of the stones they had available. In that way the resultant assemblages reflect the characteristics of the different materials so that it is difficult to recognize specific selection for individual types of tool.

The basic diagrams of different raw material use around the Inner Sound are hampered by our incomplete knowledge of the different sites, but they do provide a hint of the detail that could be confirmed, or expanded, by further study. At the outset of the study attention focused on the use of baked mudstone from Staffin Bay, but as time progressed this material was found to be less important than initially thought, with the exception of the sites at Staffin itself, and the assemblage from the excavated Mesolithic site of Sand. Even on the island of Scalpay, not far from Staffin, baked mudstone was almost completely absent. Is it possible that Sand, with the increased detail from excavation, actually holds the key for raw material use on the Mesolithic sites of the area? Until there are more dates relating to the potentially more recent assemblages from the area it is impossible to be certain, but the importance of more homogeneous stones in the Mesolithic would make sense for at this time assemblages comprised many fine regular artefacts and this may well have led to a preference for baked mudstone.

Local resources were clearly important at Sand, but the mobility of the Mesolithic population meant that material could easily be brought in from further afield when this was advantageous. Thus baked mudstone and Rùm bloodstone were particularly valued at Sand for the manufacture of regular flakes, blades and retouched tools including narrow blade microliths. Later on, as the importance of fine lithic tools fell, it is quite possible that imported materials were no longer of such value so that later sites show greater emphasis on the use of local materials. Shieldaig, however, seems to contradict this as the lithic assemblage there, which certainly includes an element of Mesolithic material, is dominated by quartz (Ballin & Saville 2003; Clarke & Griffiths 1990), though the details of the excavation are unclear. Elsewhere, material is derived from surface collection or test pitting so that the precise details of individual sites, including dates, are missing. Only more excavation on a variety of local sites from different periods could test this out.

Many of the survey sites have later dates and these tend to show less use of transported materials. At some sites microliths suggest early activity, but the assemblages are small, pending excavation. Interestingly, with the exception of Sand, it is quartz, followed by chalcedonic silica, that dominates assemblages away from Staffin. It may well be that local availability was the most important factor of raw material selection in later prehistory. Nevertheless, the population of the Inner Sound was mobile, at least by sea, until very recent times (and the rise of road transport). However, it could be argued that the central importance of mobility as the axis around which economy and society swung was greatest during the Mesolithic and it is possible that this is reflected in the movement of baked mudstone and the use of lithic raw materials around the Inner Sound.

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