The distribution of carbonised plant remains - N Sharples and T Holden

(based on a report by S Boardman)

THE MIDDLE IRON AGE DEPOSITS

Block 7.6 The broch wall

Nothing was sampled.

Block 7.5 Broch primary occupation

Thirty five samples were processed from this block (16, 34, 42, 45, 46, 52, 261, 262, 619, 657, 658, 659, 661, 680, 682, 687, 704, 722, 737, 738, 740, 744, 747, 748, 749, 752, 754, 756, 760, 764, 772, 773, 775, 779, 780). Twenty two of these contained more than ten components (16, 34, 45, 261, 262, 661, 680, 682, 687, 704, 738, 740, 747, 748, 749, 752, 756, 760, 764, 773, 779, 780). The majority of these can, on the basis of their composition, be divided into three distinct groupings.

Group 1 consists of those samples that were dominated by large quantities of barley grain, (over 11000 grains in total, with only 38 incidental oat grains). Few other identifiable components were recovered but these did include seeds of the wild taxa Brassica sp. (27 seeds) and Galeopsis sp, (10). No small-seeded species such as Stellaria media were present. The six contexts in this category (261, 680, 747, 749, 760, 773) were also the only contexts from this block with concentrations of greater than ten identifiable components per litre. All of these layers included red ashy deposits. Contexts 261, 680, 747 were part of an extensive spread of ash which probably originally covered the floor of the broch and represents a conflagration at the end of the primary occupation of the broch. The other layers within this group (749, 760, 773) are post hole or pit fills which suggest those features were open when this conflagration occurred. The cleanness of the grain and its high concentration suggest that it was a clean stored product that became charred during the conflagration.

Group 2 consists of four contexts (45, 704, 738 & 764) and is characterised by samples containing only a low concentration of cereal grain but significant numbers of Stellaria media. At least three of these deposits (45, 704 and 738) represent fills or spreads associated with the sunken compartments of the broch interior and underlie the red ashy deposits that characterised the Group 1 deposits (above). These deposits are considered likely to derive from material that was lying on, or within, floor deposits at the time of the conflagration. It is probable that the components became charred because of hot ash accumulating over them, either as a result of the burning of in situ organic layers that overlay these floors at the time of burning or following the falling of embers from above onto the broch floor. There is also an outside possibility that the botanical remains in these deposits were charred prior to the main conflagration.

Group 3 consists of a category of deposit which, on the basis of its composition, falls between Groups 1 and 2 (16, 34, 682, 740, 748, 779). They contain significant, but not large, numbers of cereal grain and also small numbers of the seeds of Stellaria media. In some cases this might just represent a mixing of the two types of deposit outlined above. They might also, as with the case of 16 and 34 which were initially thought to be equivalent to layer 680, indicate a degree of spatial variation across the red ash layer reflecting what was on the floor or in different parts of the superstructure when it burnt down.

If one includes samples 16 and 34 with the late conflagration group (Group 1) of contexts then the remaining contexts should contain elements of primary broch activity. Eleven assemblages are relevant (45, 262, 661, 704, 738, 740, 748, 752, 764, 779, 780) containing low cereal concentrations and/or the seeds of (Stellaria media).

7.5        OAT    BARLEY    WILD NO     WILD                 
EARLY                                  SPECIES               

                                                             

45                  19         86         6     77           
                                                Stellaria    

262                  9                                       

661         1       15                                       

704         1        7         23         4     15           
                                                Stellaria    

738         1       12         40         4     30           
                                                Stellaria    

740                 26         2          1                  

748                 15         7          3                  

752                 13         5          5                  

764         7       23        243         8     217          
                                                Stellaria    

779         3       20         62         4     53           
                                                Stellaria    

780         1        4                                       

42                   2         7          2                  

658         1        1                                       

659                  1         1          1                  

737                  6                                       

744                  5                                       

772                  5                                       

           15       183       476                            


7.5        OAT     BARLEY    WILD NO      WILD                  
LATE                                    SPECIES                 

                                                                

16                   125        141        9     89 Stellaria   

                                                 11 Brassica    

                                                 11 Polygonum   

34                   108        22         5                    

261                  225                                        

680         23      LOTS        56         8     27 Brassica    

                                                 10 Galeopsis   

682                  69         11         3                    

687                  11                                         

747                  86                                         

749         2        412         3         2                    

756                  13                                         

760                  193                                        

773         13       344                                        

619         1         4                                         

657                              1         1                    

754                   2                                         

            39     1592 +       234                             


Block 7.7 The wall chamber occupation

Two samples were taken (13, 17). Only 17 produced carbonised plant remains, 6 barley grains and 1 chickweed seed.

Block 4.4 The ditch and bank

Both layers (551, 561) were processed but only 551 produced a single wild seed.

Block 5.4 The ditch

5.4        OAT        BARLEY     WILD NO     WILD SPECIES   

                                                            

621                       6                                 

665                       1           1            1        

667                                   2            1        

671                                   6            5        

675            1                                            

               1          7           9                     


Seven samples were processed from this block (621, 665, 666, 667, 671, 674, 675). All but two (666, 674) produced carbonised plant remains but none had more than 10 components. The interesting feature of this assemblage is that three of these samples (665, 667, 671) contained wild species and 671 had five individual species represented. The most common cultivated species was barley (7 grains) with only one grain of oat present.

Block 6.7 The hollow

6.7        OAT        BARLEY     WILD NO     WILD SPECIES   

                                                            

229                       6           4            3        

219                       1           2            2        

226            1          2           1            1        

728                       3           4            1        

729                                   1            1        

               1          12         12                     


Nine samples were processed from this block (219, 226, 229, 708, 727, 728, 729, 730, 768). Only five of these contained carbonised plant remains (219, 226, 229, 728, 729) and only one of these (229) had more than ten components. The only noticeable feature of this rather poor assemblage is the presence of wild seeds in all of the samples with three species in 229. The cereal assemblage was dominated by barley (11 grains) with oat only appearing in one context (226).

Discussion of the Middle Iron Age activity

The internal deposits

Two different scenarios have been put forward for the accumulation of the red ashy layer, primarily Context 680. It was originally, and very plausibly, thought that it represented an accumulation of ash deriving from the superstructure, including roofing material. The, evidence from the soil thin section analysis, however, indicates that it represented in situ accumulation of laminated deposits. This was formed by a build-up of thin layers of organic material onto the floor. The intense heat above this layer was such that it was able to oxidise a depth of at least 15 cm of these floor deposits to red ash (680). At a regular depth below the surface the lessening heat down through the profile resulted in charring rather than ashing leaving a thin band of dark floor material (704). Beneath this charred layer there may originally have been a further depth of organic material but this has since rotted away. This scenario does not obviously allow for the incorporation of charred grain within layer 680. Either it would have been converted to ash if it was within or above the hot upper zone of the floor or it would have been present in high concentrations in the surviving carbonised layers of the floor such as 704, which it was not. The grain recovered from 680 and its associated contexts was clearly a quantity of grain that had been cleaned of all contaminants. It almost certainly represents the remains of a store of clean grain. The favoured explanation for its survival in the broch interior is therefore that a massive quantity of cleaned grain fell onto one area of the floor. The upper layers of the grain combined with any overlying material would have been converted to ash similar to that produced over much of the rest of the broch floor. The pile of grain must have been deep enough that at some depth (probably much greater than 15 cm) the heat was such that carbonisation rather than total oxidation took place.

The clean grain produced in the conflagration deposits was dominated by hulled six rowed barley with very few contaminants. These could all derive from a single store of clean grain. During post excavation it was considered likely that layers 16 and 34, excavated from the southern part of the broch in the first season were equivalent to the main red ash deposit 680. Their composition was, however, somewhat different in that they contained considerable numbers of chickweed (Stellaria media) seeds and did not contain the large quantities of grain. This could be seen as a demonstration of spatial variation in both preservation and distribution of debris over the broch floor. The signal in the case of these areas might indicate a mixing of straw from the broch floor (see below) and clean grain from the burned storage facility.

Below the red ash layers were a series of deposits (45, 704, 738) which are thought likely to represent charred remains of in situ floor deposits. These are characterised by small quantities of grain and elevated numbers of Stellaria media seeds. These seed assemblages could be interpreted in a number of ways but the most obvious is that they represent the seed component of threshed cereal straw. The taxa present and the relative concentrations of seeds from these layers match very well with samples of 19th century oat and barley straw used as basal thatching layers and cut from base-rich soils on South Ronaldsay, Orkney (Holden & Carter 1996). The contexts from which they derive, would in these cases suggest that the straw had been used as flooring material.

The wall chamber and external deposits

These deposits contain only low-level concentrations of identifiable charred remains. Species composition is largely the same as that recovered from the broch interior but in much reduced concentrations. Hulled barley dominates the samples with lesser numbers of primarily arable weeds. No significant context-related variation was noted and there was little evidence for in situ carbonisation of the debris. The composition of these samples is in keeping with the low-level background 'noise' that appears to have accumulated over many years in the broch and surrounding sediments. The origin of these charred remains is very likely to be the domestic hearth as a result of routine processing techniques. Grain drying around the hearth prior to milling or de-husking of grain in the fire (gradden) are likely sources of regular amounts of grain becoming charred over many years (see for example Fenton 1982). It is also possible that considerable quantities of carbonised debris may have been cleared from the interior of the block following its re-occupation after the fire. These too may form an element of the background signal.

THE LATE IRON AGE OCCUPATION

BLOCK 7.3 The broch re-occupation

7.3     OAT        BARLEY     WILD NO    WILD SPECIES                

                                                                     

759                    45         19           1        17           
                                                        Stellaria    

732         1          45         6            3                     

726                   356                                            

684         3         393         2            2                     

679                    59         1            1                     

616                   145         2            1                     

578         1          12                                            

549         10        204                                            

28                     25         7            3                     

19                     24         23           7        10           
                                                        Stellaria    

259                    2                                             

635                    1                                             

670                    3                                             

762                               1            1                     

            15        1314        61                                 


Seventeen layers were processed from this block (19, 28, 259, 549, 578, 592, 608, 616, 635, 670, 679, 684, 726, 732, 759, 762, 770). All but three (592, 608, 770) of these samples contained carbonised plant remains and ten of these (19, 28, 549, 578, 616, 679, 684, 726, 732, 759, 762, 770) had more than ten components per litre. The overwhelming bulk of the cereal present was barley. Only 15 oat grains were present compared to 1314 barley grains. Many of these contexts had high concentrations with four (549, 616, 684, 726) having more than ten components per litre. The two (684, 726) richest samples come from post hole fills. 549 is a red ash layer, probably derived from underlying layer 680, and 616 is a charcoal spread initially presumed to represent in situ activity. These four samples possess exactly the same composition (ie large numbers of grain and no small weed seeds) as the majority of samples from the red ash layers which mark the end of the primary phase of occupation (Block 7.5). It would seem very likely that both the packing material from post or stone holes and the layers and spreads represented by these four samples consists of reworked material deriving from these earlier conflagration deposits. It is of interest that the composition of the two samples that were taken from the first years excavation in the outer part of the broch (19 and 20) match well with the samples from the underlying ashy deposits in that part of the broch interior (ie reduced quantities of grain with relatively larger numbers of small weed seeds such as Stellaria media). Contexts 19 and 28 are therefore also likely to contain reworked material from the earlier conflagration deposits and confirm the heterogeneous nature the deposit across the broch floor.

With regard to the remaining deposits from this block it is difficult, from the plant remains alone to determine whether the reduced concentration of cereal grain is a result of a dilution of residual conflagration material. It is possible that features such as 759 for example, with its relatively high weed seed component, could be contemporary with the features from which they were recovered.

Block 7.4 The broch reoccupation

7.4      OAT        BARLEY      WILD NO    WILD SPECIES             

                                                                    

9                       10          5            3                  

14                      101         24           3       21         
                                                         Stellaria  

654                     133         7            3                  

692                     22                                          

                        266         36                              


Only five layers were processed from this block (9, 14, 29, 654, 692). All but one (29) produced carbonised plant remains and they all had more than ten components. Two had densities greater than ten components per litre (654, 692). 654 was backing to wall 513 and 692 was a post hole fill. The overwhelming bulk of the assemblage was barley grain with no oats present. The situation with this block is similar to that outlined above for Block 7.3 in that much of the material derives from the earlier conflagration deposits, the concentrations of which have masked any contemporary signals. As with Block 7.3 and 7.5 the samples from the early excavations in the southern part of the broch ( 9 & 14) contained relatively high proportions of small weed seeds in conjunction with similar concentrations of cereal grain.

Block 7.2 The final occupation of the broch

Seventeen samples were processed from this block (8, 15, 258, 539, 543, 557, 563, 577, 583, 591, 613, 645, 681, 683, 685, 686, 766). All but one (591) of these samples contained carbonised plant remains. Furthermore all but two (8, 557) of these samples contained more than 10 components. Six samples had densities of over 10 components per litre of soil (15, 613, 681, 683, 685) and one (766) had a density of 106 components per litre. All but two of these rich soil layers were post hole or gully fills and most represent cereal assemblages dominated by barley (1482 to 13 oat grains).

Context 613, a charcoal layer, and 15, a soil and rubble layer, are both likely to contain redeposited material. In support of this, Context 15 differs from all other contexts in this Block by having a high number of barley grains and also a relatively high number of smaller weed seeds (Stellaria media). This accords well with the composition of many other samples taken from the excavations in the southern part of the broch interior and suggests that the redeposited material derived from that part of the broch. Contexts 681, 683, 685 and 766, a suite of negative features from the broch interior, all possess high quantities of clean grain. This too is likely to have derived from the red ashy layers produced at the end of the first phase of broch activity (eg 680) and through which these features were cut.

Samples 258 and 613 stand out as being somewhat different from the remainder of the samples from this block. They possess very few cereal grains but considerable numbers of arable weed seeds, particularly dock (Rumex sp). Their composition would argue against them being redeposited ashy material of the type recorded from other Block 7.5 deposits. The large number of dock seeds is certainly not typical of other seed assemblages from this site and they would appear to have been concentrated in some manner. This could happen by, for example, the accidental burning of a rodent hoard or a single mature dock plant. However, the nature of the contexts from which they were recovered, ie layers of rubble and soil from between two revetment walls, suggest that they are not in their original location making more detailed interpretation impossible.

The remainder of the samples (8, 539, 543, 557, 563, 577, 645, 686) contain only a low number of cereal grains, dominated by barley with rare oats grains. This material could derive from small quantities of reworked early conflagration material but could also represent background concentrations of charred plant remains typical of domestic activity in the broch. They could therefore be contemporary with the features from which they were recovered.

7.2      OAT    BARLEY      WILD NO    WILD SPECIES                   

                                                                      

766                 209         3            2                        

686                 29                                                

685       3         331         9            2                        

683       1         392         2            1                        

681       3         152                                               

645                 32                                                

613                  1         317           9        247 Rumex       
                                                      20 Stellaria    
                                                      15 Polygonum    

583                 64                                                

577                 11                                                

563                 11                                                

543       1         74                                                

539       2         60                                                

258       1          4          54           6        35 Rumex        

15        1         98          34           2        33 Stellaria    

557       1          8                                                

8                    6          2            2                        

          13       1482        421                                    


Discussion of the Late Iron Age broch deposits

A high proportion of the later features of the broch contain material that has been reworked from the conflagration deposits of the middle Iron Age. Most negative features from the later phases were cut into the red-ash layer 680 and slumping of the edges will have given rise to mixing. Much of the construction material, packing, makeup etc, will have been scraped up from the floor of the broch and will therefore contain remnants of earlier deposits. It was recognised above that the samples taken during the first excavation in the southern part of the broch contained higher than average numbers of Stellaria media seeds and a relatively low grain concentration. This is also the case with samples taken from the later phases of the southern parts of the broch. This observation supports the case for the contamination of later samples by material reworked from those below them.

Few samples have been identified as being uncomtaminated. Context 759 is one such possibility, the signal indicating the burning of a partially cleaned crop product or cereal straw. It is, however, clear than any small assemblages of material contemporary with the later occupations of the broch may easily have been swamped by material reworked from earlier sediments.

The composition of two samples (258, 613) from Block 7.2 are noticably different in composition to those from elsewhere on the site in that they contain large numbers of Rumex sp fruits (dock). Their location as rubble deposits between two revetment walls, however, provides no basis to interpret this assemblage in anything but the most general terms. It was noted above that rodent hoards or the burning or a single dock plant could have produced the numbers of fruits recovered here.

Block 6.3 House 1

6.3       OAT     BARLEY     WILD NO     WILD SPECIES             

                                                                  

559                   7                                           

554         1         7                                           

567                   4                                           

569                   7                                           

575                   2                                           

576                   3           2            2                  

            1         30          2                               


Six samples were processed from this block (554, 559, 567, 569, 575, 576). All of these samples produced carbonised plant remains but only one sample (559) produced more than ten components. The assemblage is unremarkable, being dominated by barley (34 grains) with only one oat grain and 2 wild seeds present. These provide an indication of the type of background levels of carbonised grain present in domestic contexts across the site.

Block 6.4 House 1

6.4        OAT    BARLEY     WILD NO     WILD SPECIES              

                                                                   

702                   4           7            5                   

707         2         55          2            1                   

617                   1                                            

668                               2            2                   

669                               2            1                   

693                   1                                            

700                   1           1            1                   

706                   1                                            

711                   2                                            

            2         65         14                                


Twelve samples were processed from this block (617, 668, 669, 693, 698, 700, 702, 706, 707, 710, 711, 739). Of these only five failed to produce carbonised plant remains (211, 698, 710, 711, 739). Two samples (702, 707) contained more than ten components and one of these (707) had a relatively high density of remains (5.5 components per litre). This was a hearth at the centre of the house, 707. The cereal assemblage was dominated by barley with only one context producing oat (2 grains compared to 55 barley). Context 707 represents one of the few deposits that is likely to have become charred in situ. It is therefore likely to be contemporary with the use of the building and provides some understanding of the quantities of grain that can become charred in domestic hearths of the period.

Block 6.6 House 1

6.6       OAT      BARLEY     WILD NO    WILD SPECIES                   

                                                                        

673        5         165         63            9        45 Stellaria    

641                   1                                                 

672                   1                                                 

691        2          4                                                 

725                   5                                                 

           7         176         63                                     


Seven samples were processed from this block (634, 641, 672, 673, 691, 709, 725). Five of these samples contained carbonised plant remains (641, 672, 673, 691, 725) but only one (673) had more than ten items. This had a large assemblage of 233 components with a density of 16.6 components per litre. This assemblage is dominated by barley but almost 30% of the assemblage is wild seeds with 9 different species represented and a large assemblage of Stellaria media. Context 673 is a dump of loose rubble and soil placed as a backing to wall 630. Wild species were absent from the other samples. Barley dominated the cereal assemblage with only 5 grains of oat from 673 and two from 691.

Block 5.3 Houses 2 and 3

5.3        OAT     BARLEY     WILD NO    WILD SPECIES              

                                                                   

650                               11           3                   

552                    4                                           

555                    2                                           

637                    2                                           

646                    1                                           

                       9          12                               


Seven samples were processed from this block (251, 552, 555, 637, 646, 650, 651) and all but two of these (251, 651) contained carbonised plant remains. However, the largest sample (650), a rubble dump, had only 11 identifiable components. The remaining assemblage consisted of ten barley grains with no oat and only one other wild seed was present in this block. The composition of these samples is in accordance with the low levels of cereal grain recovered over many of the external broch features.

Block 4.2 House 4

Four samples were processed from this block (514, 562, 574, 598). Two (514, 562) produced carbonised plant remains and these only contained a total of 6 components, five of which were barley grains.

Block 2.1 Houses 5 & 6

Seven samples were taken from this block (237, 266, 531, 570, 571, 594, 615). Of these only four samples (237, 266, 570, 615) produced any carbonised plant remains and only one (237) had more than ten components. All the identified components were cereal grains with one exception, a wild seed from 266. Barley was twice as common as oat in the largest sample. In view of the excavators observation that rabbits disturbance had occurred in these loosely compacted layers the significance of these higher than average proportions of oat grain are of uncertain value.

Block 2.3

The one sample (611) from this block contained one barley grain and one weed seed.

Block 3.2

The two samples (214, 217) processed both produced carbonised plant material; 217 an oat and a barley grain; 227 two wild seeds.

Block 12.2 House 7

Three sample were taken from this block (48, 50, 58). All of these produced carbonised plant remains and one (48) produced more than ten components. All of the samples have more wild seeds than cereal grains and all but one of these were chickweed seeds. The cereals were all barley.

Block 12.3

Three samples were processed from this block (59, 64, 151). All the samples contained carbonised plant remains and two samples (59, 151) had more than ten components. 151 is solely barley, 59 and 64 are dominated by wild seeds with chickweed the dominant species.

Block 12.4

Five samples were processed from this block (77, 79, 141, 143, 150). All of these samples produced carbonised plant remains and two (77, 79) had more than ten components. The assemblage is dominated by wild seeds with ten species present. Brassicas and chickweed are the most common. All the cereal grains were barley.

Discussion of the external settlement in early phase 3

The charred plant remains recovered from these blocks can largely be characterised as having low numbers of cereal grain with an occasional additional weed seed element. They are consistent with the low level of background noise that has already been discussed for them middle Iron Age external deposits (above). Most are likely to be derived from cereal processing activities in, or around, the domestic hearth which later become incorporated into construction deposits, floors etc. Few primary deposits have been identified, making Context 707, an in situ hearth deposit, of some significance. This deposit contained 55 barley grains and is likely to represent a good example of one of the small-scale losses of grain thought to be responsible for the background levels noted in this and other parts of the site. Loss of grain is likely to have been commonplace in households where piecemeal, possibly daily drying or processing of grain around the domestic hearth was practiced. It is probable that the disposal of hearth debris containing grain would have caused the gradual accumulation of low-level concentrations of grain which are often observed in many sediment contexts on intensively occupied settlements.

Hulled barley is the main crop species present with oats only occurring sporadically. Context 237 (Block 2.1) is an exception to this with a 2:1 ratio of barley to oat (ie 16 barley and 8 oat grains) present. This part of the external settlement is, however, reported to have suffered from significant disturbance by rabbits. This apparent increase in the presence of oat must therefore be treated with some caution. This context aside, the proportions of oat present would be in keeping with their being weeds of the barley which, by virtue of the size and density of the grain and the growth habit of the plant, were not easily separated from the crop.

Block 6.2 House 8

6.2        OAT    BARLEY     WILD NO    WILD SPECIES               

                                                                   

614                   16         2            2                    

620         1         12                                           

631                                                    8 FLAX      

639         1         10                                           

248         2         4                                            

556                   5                                            

593                   5                                            

595                   3                                            

612                   1                                            

647                   1          1            1                    

648                   1          1            1                    

652                   1                                            

653                   5                                            

664                   2                                            

            4         66         4                                 


Sixteen samples were processed from this block (248, 556, 593, 595, 607, 610, 612, 614, 620, 631, 639, 647, 648, 652, 653, 664). All but two (607, 610) contained carbonised plant remains and three samples (614, 620, 639) had more than ten components though none has a high density. These samples contain the same low background levels of cereal noted over much of the external features. It is overwhelmingly dominated by barley (66 grains) with oat almost absent (4 grains). Wild seeds are present in only three contexts; numbering 4 seeds.

One sample (631) consisted solely of eight grains of flax which have been dated to (AA-13803) 1275±55 cal AD669-786. These came from the hearth in the centre of the structure and can reasonably be assumed to have been charred in situ.

Block 6.1 The final occupation of the external settlement

6.1        OAT    BARLEY     WILD NO    WILD SPECIES               

                                                                   

96          1         3          9            4                    

260        11         16         3            1                    

533         3         8          4            1                    

239         4                                                      

534         1         2          1            1                    

558         1         3                                            

560                   4                                            

640                   1                                            

           21         37         17                                


Eight samples were taken from this block (96, 239, 260, 533, 534, 558, 560, 640). All of these produced carbonised plant remains and three produced more than ten components (96, 260, 533) though none had a particularly high density of material. One layer (96) contained an assemblage of wild seeds (four species, nine seeds) and these also occurred in three other layers (260, 533, 534) though in these only single species were noted. The crop species were dominated by barley (37 grains) but oat was also significant (21 grains) particularly in 260, one of the final layers. These grains have, however, been dated to cal AD230-377. If residual, as suggested by the excavator, then they are likely to represent a weedy species of oat. However, the relatively large number of these in the absence of other weed taxa would argue against this. This problem of interpretation remains unresolved at present.

Block 3.1 The fill of the middle Iron Age ditch

All of the four samples (205, 206, 209, 210) processed produced carbonised plant remains but the largest sample (205) contained only two grains, one oat and one barley.

Block 4.1 The fill of the middle Iron Age ditch

Neither of the two samples (508, 515) processed contained carbonised plant remains.

Block 5.2 The fill of the middle Iron Age ditch

5.2        OAT    BARLEY     WILD NO   WILD SPECIES              

                                                                 

249         2         19                                         

250        17         75         5           4                   

525         1         10                                         

564         2         10                                         

568         2         13                                         

224                   1                                          

252         2         1          1           1                   

502                              2           2                   

520         1         7                                          

522         2                                                    

524                   3                                          

545         1         7                                          

602                   4          2           2                   

           30        150        10                               


Thirteen samples were processed (224, 249, 250, 252, 502, 520, 522, 524, 525, 545, 564, 568, 602). All of these contained carbonised plant remains and five (249, 250, 525, 564, 568) contained more than ten identified components. One sample (250) contained approximately 101 identified remains from only 9 litres of soil giving a density of 11.2 components per litre. This was one of a number of red clay layers which were interpreted as ash dumps. Wild seeds were relatively uncommon in these layers occurring in only four samples; context 250 only produced 5 examples. Barley was the dominant crop with 150 grains compared to 30 of oat. Oats reach appreciable proportions in these samples which, from Context 250, were dated to cal AD687-885. In the absence of an appreciable weed seed elements it is becoming more likely that these represent traces of a crop rather than a cereal weed.

Block 12.1 House 9

One sample (157) contained no carbonised plant remains.

Block 9.2 The middens on the southern slopes

9.2       OAT      BARLEY    WILD NO      WILD SPECIES                

                                                                      

144        17        48          5             3                      

129                  16         14             3         12           
                                                         Stellaria    

402        13       243                                               

403        7         75                                               

421                 688          1                                    

128                  1                                                

423                  8                                                

           37       1079        20                                    


An unknown number of samples was processed from this block. Seven produced carbonised plant remains (128, 129, 144, 402, 403, 421, 423). Five of these samples (129, 144, 402, 403, 421) contained more than 10 components and one (421) had a very high density (29.3). This layer came from above the only structure identified in this area and this may be significant. The most important features of the assemblage in this block was the absence of wild seeds and the importance of oat. One sample (129) had a small collection of chickweed seeds in an otherwise poor assemblage but this was from a small test pit unconnected to the main excavation.

Block 9.3

9.3        OAT      BARLEY     WILD NO    WILD SPECIES               

                                                                     

130                   50          8            4                     

404        21         330         46           5        27           
                                                        Stellaria    

405         4         23          3            2                     

422        28         262         22           6        11           
                                                        Stellaria    

424        54         108         4            4                     

425         4         24          8            2                     

427        18         82          3            2                     

433         2         20          7            2                     

131                    2                                             

427D        1          1                                             

434                    1                                             

           132        903        101                                 


An unknown number of samples was processed from this block. Eleven produced carbonised plant remains (130, 131, 404, 405, 422, 424, 425, 427, 427d, 433, 434) and all but two (427d, 434) of these had more than ten components. None of the samples were particularly productive and the quantity of remains is directly equivalent to the amount of soil processed. The cereal assemblage is dominated by barley grains but again oat is present in significant quantities (131 grains compared to 911 barley grains). The samples from this Block contrast with the majority of those recovered from block 9.2 in that they contain numerous seeds of Stellaria media (chickweed - a sample of 27 seeds in 404 and 11 seeds in 422).

Block 10.3, 10.4 Activity to the north east

No samples taken.

Block 10.5 Activity to the north east

One sample (104) contained one barley grain.

Discussion of the external setttlement in late phase 3

The deposits from House 8 and the final occupation layers contain similar regular concentrations of plant remains to the structures from the earlier phases, consisting of low numbers (less than 12 items per litre of sediment) of cereal grain and occasional weed seeds. This is probably an indication that the same type of formation process, ie occasional charring and discarding of grain from the domestic hearth, were occurring and that reworking of both earlier and contemporary sediments must clearly have occurred. The ditch-fill and midden deposits are less predictable with some blocks producing negligible remains and other producing relatively high concentrations. This variability undoubtedly reflects the different formation processes and helps to distinguish deliberate dumping of domestic refuse from natural sedimentation or backfilling using sterile sediments.

Hulled barley is still the dominant grain throughout the phase but oat grains are beginning to occur with a greater regularity and occasionally in significant numbers (eg 260 Block 6.1, and 250 Block 5.2 and particularly in the middens on the southern slopes Block 9.2 and 9.3). In some contexts oat accounts for up to a third of the total number of grain (eg 427). These relatively high proportions of oats strongly suggest that they represent the remains of a crop rather than a contaminant.

The weed seed element throughout these blocks is approximately similar to that recovered from previous blocks and would not appear to offer any significant change in the field ecology.

Block 7.1 The broch destruction

Thirty three samples were taken from this block (6, 10, 11, 81, 87, 207, 256, 263, 268, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 286, 287, 290, 291, 292, 293, 294, 295, 297, 298, 299, 500, 501, 507). Of these all but six (10, 11, 275, 291, 295) contained carbonised plant remains. Most of these samples contained only one or two components but five samples had more than ten components (6, 81, 256, 263, 277). Only one of these had a reasonably high density of (5.6) components per litre. This sample is from layer (6) the general rubble spread overlying the broch and indicates that the composition of these sediments is far from homogenous. The assemblage from 6 contained only barley (56 grains) and this is anomalous as otherwise the assemblages from this block tend to have a higher proportion of oat (66 grains compared to 33). Weeds are relatively rare occurring in only five samples with two contexts providing the bulk of the assemblage (81, 263). Both are dominated by Stellara media. Both are layers at the base of the stratigraphic succession for this block.

7.1        OAT    BARLEY     WILD NO     WILD SPECIES              

                                                                   

6                     56                                           

81                    1          11            4                   

256         8         22                                           

263        15                     6            1                   

277         5         6                                            

87                                1            1                   

207         1                                                      

268         1                                                      

274         2                                                      

276         3                                                      

278         1                                                      

279         2                                                      

280                   1                                            

281         3         1                                            

282                                                                

283         3                                                      

284         1                                                      

286         5                                                      

290         2                                                      

292         3         2                                            

293         5         3                                            

294         2                                                      

298         3                                                      

299         1                                                      

500                   1           1            1                   

501                               1            1                   

507                   6                                            

           66         99         20                                

The uncertainty of the origin of the charred remains precludes any detailed analysis of their significance in these sediments. The concentration of plant remains in these samples is not high but there is a clear trend towards oat being the dominant over barley (this is true in all but four of the samples).

Miscellaneous blocks

Block 2.2

The one sample (589) from this block contained four grains, 3 barley and 1 oat.

Block 5.1 Modern topsoil

Seven samples were processed from this block (221, 232, 243, 518, 527, 542, 544). Five of these (221, 232, 243, 518, 542) contained small quantities of carbonised plant remains. Only cereal grains were present, comprising barley (7) and oat (11).

Block 5.5

5.5          OAT    BARLEY      WILD NO    WILD SPECIES              

                                                                     

581          23          8          1            1                   

603                      7                                           

             23         15          1                                


Three samples were taken from this block (581, 601, 603). Only two samples (581, 603) produced carbonised plant remains. One sample (581) produced 33 identifiable components and it is interesting that this assemblage of cereals (only one wild species was present) was dominated by oat; 23 grains compared to eight grains of barley. This context is a shallow scoop of unknown date lying to the north of the ditch.

Block 6.5

6.5        OAT       BARLEY    WILD NO    WILD SPECIES              

                                                                    

600                    5                                            

604                    4                                            

605                               1            1                    

                       9          1                                 


Four samples were processed from this block (599, 600, 604, 605). One sample (599) had no carbonised plant remains AND none had more than ten components. The samples were all barley grains with the exception of one wild seed from 605.

Block 8.2

One sample (142) from this block produced an assemblage of 20 components which might be considered unusual for this, a supposed naturally derived sediment. The assemblage was dominated by chickweed (6 seeds) with only five barley grains present.

Block 9.1 Modern topsoil

An unknown number of samples was processed from this block but only one (401) produced any material. A large quantity of soil was sieved so even though the density of components per litre was low a sizeable assemblage was recovered. The cereal assemblage was dominated by oat (74 grains to 46 barley) with only a negligible quantity of wild seeds.

Block 10.1 Modern topsoil

Three samples (301, 302, 313) were taken from this block and two (302, 313) had small quantities of carbonised plant remains present. The only significant feature to note is the dominance of oat over barley in (6 oat to 3 barley).

Block 10.2 Grave fill

Four samples were taken from this block (306, 308, 317, 318). All produced more than ten component carbonised plant elements. The cereal assemblage consisted of 51 barley grains compared to 38 oat grains, indicating the importance of oat particularly as most of the barley is derived from one sample (317). It is likely that all of this material is derived from earlier assemblages as the samples were taken from grave fills which are presumed to be simply redeposited soil from the excavation of the grave.