ORIGINAL ARTICLE

The Transition from the Later Stone Age to Iron Agein Kondoa, Central Tanzania

Emanuel Thomas Kessy

Published online: 31 August 2013# Springer Science+Business Media New York 2013

Abstract Many scholars assume that the spread of Iron Age (IA) agropastoralismtraditions to Sub-Saharan Africa was associated with the domination, assimilation, ordislocation of Later Stone Age (LSA) autochthonous populations. Archaeologicaldata from Kondoa, central Tanzania show evidence of interaction between IAagropastoralists and LSA hunter-gatherers around 1030 years BP. Despite that, re-placement of the LSA traditions seems to have taken a considerably slow pace,leading to the suggestion that autochthonous LSA groups were not displaced orassimilated by IA people but became agropastoralists through a process ofacculturation. This outcome raises questions about the reliability of the assim-ilation or displacement models typically used by scholars to account for the fateof prehistoric LSA hunter-gatherers during contact with IA agropastoralists inSub-Saharan Africa.

Résumé Beaucoup de chercheurs présument que l'expansion des traditions agro-pastoralistes de l'Age de Fer (AF) en Afrique sub-Saharienne a impliqué la domina-tion, l'assimilation, ou la dislocation des populations autochtones de l'Age de PierreTardif (APT). Les données archéologiques de Kondoa, en Tanzanie centrale,documentent les intéractions entre agro-pastoralistes de l'AF et chasseurs-cueilleursde l'APT vers 1030 BP. Ces données indiquent que le remplacement des traditionsde l'APT semble s'être déroulé relativement lentement, et suggèrent donc que lesgroupes autochtones de l'APT ne furent pas chassés ou assimilés par les popu-lations de l'AF mais qu'ils sont devenus des agro-pastoralistes par un processusd'acculturation. Ces résultats mettent en question les modèles de dislocationtypiquement invoqués par les chercheurs pour expliquer le destin des chasseurs-cueilleurs prehistoriques de l'APT suite à leur contact avec les agro-pastoralistes del'AF en Afrique sub-Saharienne.

Afr Archaeol Rev (2013) 30:225–252DOI 10.1007/s10437-013-9141-4

E. T. Kessy (*)Department of History and Archaeology, University of Dar es Salaam, P.O. Box 35050,Dar es Salaam, Tanzaniae-mail: etkessy@alumni.sfu.ca

E. T. Kessye-mail: etkessy@gmail.com

Keywords Later Stone Age . Iron Age . Hunter-gatherers . Agropastoralists . Kondoa,central Tanzania

Background

This paper presents an archaeological case study that examines direct evidence relatingto questions of acculturation in the Kondoa region of central Tanzania. It focuses on thevillages of Lusangi and Baura, located in the Pahi Ward of Kondoa (Fig. 1). Thetopography of Kondoa consists of the undulating Irangi Hills with flat areas in between.Generally, the flat areas surrounding the Irangi Hills are drier and less fertile than thehills themselves. For example, the mean annual rainfall at Kondoa town (1,390 m a.s.l.),which is located on the lower part of the Irangi Hills, is about 600 mm, while for Haubimission, located on the upper area (1,700 m a.s.l.), is about 900 mm. There is apronounced variation in annual rainfall in the area from year to year. The minimumrecorded value was 509 mm in 1964/1965 and the maximum was 1,416 mm in1967/1968 (Christiansson 1981; Dejene et al. 1997; Mung'ong'o 1999). On thisbasis, the Irangi Hills support higher populations than the adjacent areas.

Fig. 1 The study area: Irangi Hills, Kondoa District, central Tanzania

226 Afr Archaeol Rev (2013) 30:225–252

The prehistory of Kondoa is relatively poorly documented despite early recogni-tion of the archaeological potential of the area. Early archaeology of the area wascharacterized by exploration of rock art and documentation of a few Iron Age (IA)sites (Fosbrooke 1950; Fozzard 1959; Kohl-Larsen 1943; Kohl-Larsen and Kohl-Larsen1938; Leakey 1950; Ten Raa 1974). Since the 1960s, a number of archaeologicalexcavations were carried out, including the work of Inskeep (1962) at Kisese IIrockshelter, Liesegang (1975) and Masao (1979) at Irangi Hills, Sutton (1968) atSandawe, and Lane (2009) at Haubi. Examination of the Kisese II rockshelter byInskeep (1962) recovered Middle Stone Age (MSA) and Later Stone Age (LSA)artifacts with an intermediate MSA–LSA industry that dates to 18,190 years BP. A dateof 1800 BP was secured for Sandawe Early Iron Age (EIA) Lelesu pottery (Mehlman1989; Sutton 1968). Liesegang's (1975) and Masao's (1979) investigations of the IrangiHills suggested that the LSA industry was widely spread in central Tanzania by 3500 to1000 BP, which was followed by the spread of IA traditions.

Models of the Impact of Bantu Speakers' Movements to Sub-Saharan Africa

Some scholars have proposed that before 2,500 years ago, with the exception of a smallsection of the East African Rift Valley, the whole of Sub-Saharan Africa was inhabited byLSA hunter-gatherers: allegedly Khoisan speakers and so-called Pygmies (Phillipson2005; Sutton 1994–1995; Vansina 1994–1995). However, immediately following thattime, IA agropastoralists, suggested to have been Bantu speakers, left West Africa andspread to Central, Eastern, and Southern Africa. In their migrations, the IA peoples cameinto contact with autochthonous LSA populations. The question of the nature of thecontacts between LSA hunter-gatherers and advancing IA agropastoralists has led archae-ologists to propose at least three interaction models-namely, displacement, assimilation,and acculturation-to describe the fate of LSA hunting-gathering communities at the onsetof IA agropastoralist dispersal to sub-Saharan Africa (Denbow 1990; Phillipson 2005).

The displacement model assumes that the spread of Bantu-speaking peoples south ofthe Equator resulted in the dislocation of LSA hunter-gatherers (Denbow 1990; Phillipson2005; van der Merwe 1980). This model accounts for why autochthonous LSA peoplestoday are represented by scattered groups of minority populations. The assimilationmodelsuggests that by the early first millennium AD, most LSA hunter-gatherers were absorbedby more technologically sophisticated IA agropastoralists, whose presence is identified inthe region by pottery and evidence of iron-working (Chittick 1975; Denbow 1990: 141;Phillipson 2005; van der Merwe 1980).

The acculturation model suggests that the IA peoples involved in the formativeperiod in most areas of Eastern and Southern Africa were descendants of LSA hunter-gatherers. This model does not involve assimilation or displacement, but ratherdiffusion of cultural elements from neighboring agriculturalists or pastoralists tohunter-gatherers (Stiles 2001, 2006; Vansina 1994–1995, 1995). Acquiring farmingand pastoral technology from their neighbors, the hunter-gatherers becamefarmers and adopted the language of the farmers. Although these models havebeen discussed in the archaeological and anthropological literature for some time,there has been no convincing evidence to evaluate them. There are no adequatedata to explain why or how LSA hunter-gatherers were assimilated, eliminated,

Afr Archaeol Rev (2013) 30:225–252 227

or developed into farmers or herders (see Kessy 2005). These unresolvedquestions form the basis of the present work.

Kondoa is an appropriate location for approaching such questions for severalreasons. First, there have been several reports of sites consisting of both LSA andIA cultural remains (Masao 1979; Odner 1971). This evidence suggests an interactionbetween the two cultures. Secondly, while the LSA industry has been relatively moreexplored there, the IA remained poorly studied, in particular regarding its chronologyand relationship to the LSA (see Kessy 2005).

Methods of Data Collection

Survey

The survey involved systematic surface walkover and shovel-test pits (STPs). Themain reason for adopting systematic sampling was to establish the surface andsubsurface occurrence and patterning of different sites on the landscape, after whichthe results would be used to determine excavation sequences. This means that, oncethe extent of the survey area was identified, it was divided into equally spacedtransects for site search. At each location, a 200-m-wide transect was surveyed and0.5×0.5 m STPs were placed at intervals of 0.5 km along each transect (Figs. 2 and 3).Most of the STPs were excavated to 0.50 or 0.60 m below the surface. As seen inTable 1, the total area covered by the survey was 17.5 km2, with 50 % coverage of theresearch universe. In total, the whole project excavated 76 STPs, 43 of which werefrom Baura and 33 from Lusangi (Figs. 2 and 3).

Excavation Strategies

The excavations aimed at assessing and complementing the survey results.Excavations were also important because they included trenches in rockshelters notincluded in the survey. With a few exceptions, excavation trenches were 1×2 m indimension. All excavations were carried out in arbitrary levels within natural layers atintervals of 0.10 and 0.20 m, except unit 3 at Markasi Lusangi 2, which wasexcavated by natural layers. Three sites were selected for excavation at Baura andfour at Lusangi (Figs. 2 and 3).

Survey and Excavation Results

The survey recovered many sites with evidence of LSA and IA material remains.However, only seven sites were examined in detail, three of which were located atBaura and four at Lusangi (Figs. 2 and 3). Survey results indicate that the LSA and IAsites were widely distributed on the landscape. The overall distribution patterns ofcultural materials in the Baura and Lusangi surveyed areas suggest that LSA and IApeoples selected similar locations for habitation (see also Lane 2009: 271 for Haubisurvey results).

228 Afr Archaeol Rev (2013) 30:225–252

A total of 16 excavation trenches were completed in the entire project, six of whichwere from Baura, while ten were from Lusangi (Table 2). Three open-air sites wereexcavated at Baura (Fig. 2). Two of these were iron-working areas where one bowlfurnace was recovered from each (Fig. 4). The Lusangi excavation involved four sites(Fig. 3). Of the ten trenches excavated at Lusangi, two were located in rockshelters,while eight were at open-air sites. One of the open-air excavations was an iron-working area. The significance of excavating Lusangi was twofold. First, it provideddata for comparison with Baura. Second, it made evaluation between the open-air androckshelter sites possible. As with the survey, most of the excavated areas includingopen-air sites and rockshelters produced exclusively LSA artifacts in their lowersequences, while the upper levels produced a mixture of LSA and IA artifacts(Table 2). This showed similarity in sequences of the cultural materials and artifacttypes not only between rockshelters and open-air sites but in most areas where thesurvey took place.

In the case of excavation, there were a few exceptions to this pattern. For example,unit 1 at Baura site 1 produced almost exclusively LSA artifacts. A few unitsproduced only a mixture of LSA and IA materials (Table 2). These include Baurasite 1—unit 4, site 2—unit 1, and site 3—unit 1. Others include Lusangi 1—unit 2

Fig. 2 Location of sites and STPs at Baura

Afr Archaeol Rev (2013) 30:225–252 229

and Lusangi 3—unit 2. For the purpose of clarity, the lower stratigraphic sequences thatare composed of lithic artifacts exclusively will henceforth be categorized as LSA, whilethe upper levels with a mixture of iron-working and lithic artifact remains will beregarded as IA.

Table 1 Site survey samplingstrategies

Area name Area demarcatedfor survey in km2

Area that received totalsurvey coverage in km2

Numberof STPs

Baura 9.5 4.7 (50 %) 43

Lusangi 8 4.0 (50 %) 33

Total 17.5 8.7 (50 %) 76

Fig. 3 Location of sites and STPs at Lusangi

230 Afr Archaeol Rev (2013) 30:225–252

Table 2 Stratigraphic sequence of artifacts at Baura and Lusangi

Site name Unit no. (site type) Lower sequences Upper sequences

Baura 1 1 (open air) Exclusively LSA Exclusively LSA

2 (open air) Exclusively LSA Mixture of LSA and IA

3 (open air) Exclusively LSA Mixture of LSA and IA

4 (open air) Mixture of LSA and IA Mixture of LSA and IA

+Two iron-working sites (includes smelting furnaces at Baura 2 and 3)

Lusangi 1 1 (rockshelter) Exclusively LSA Mixture of LSA and IA

2 (open air) Mixture of LSA and IA Mixture of LSA and IA

3 (open air) Exclusively LSA Mixture of LSA and IA

Markasi Lusangi 2 1 (open air) Exclusively LSA Mixture of LSA and IA

2 (open air) Exclusively LSA Mixture of LSA and IA

3 (rockshelter) Exclusively LSA Mixture of LSA and IA

4 (open air) Exclusively LSA Mixture of LSA and IA

Lusangi 3 1 (open air) Exclusively LSA Mixture of LSA and IA

2 (open air) Mixture of LSA and IA Mixture of LSA and IA

Lusangi 4 1 (open air) Exclusively LSA Mixture of LSA and IA

Fig. 4 Above left Baura 2 unit 1 furnace vertical cross-section; below left horizontal furnace outline. Aboveright Baura 3 unit 1 furnace vertical cross-section; below left horizontal furnace outline

Afr Archaeol Rev (2013) 30:225–252 231

Chronology of Baura and Lusangi Sites

Four charcoal samples from Baura were tested for chronology. Unit 1 at Baura 1 yielded adate of 2500 years BP from a context with exclusively LSA artifacts (Table 3). Unit 2 atBaura 1 yielded a date of 460 years BP from a context containing a mixture of LSA and IAmaterials. This date, therefore, marks the transition from the LSA to IA at Baura. The twofurnaces at Baura 2 and 3 seem to have been almost contemporary because they yieldeddates of 120 and 140 years BP. At Lusangi, five charcoal samples were taken forchronological testing. A date of 1030 years BP from Markasi Lusangi 2—unit 2, level 4suggests a transition period from LSA to IA (Table 3, note materials associated with thecharcoal sample), while that of 760 years BP from unit 4 indicates that iron-working wasprobably practiced on a large scale at the site. Investigation at Haubi area (adjacent to bothBaura and Lusangi) indicates accelerated gully erosion between AD 1200 and 1300,leading to a suggestion of advanced land clearance due to increased iron production, aswell as agropastoralism (Lane et al. 2001; Lane 2009). A date of 140 years BP fromLusangi 1—unit 2 suggests that lithic artifacts were still used side by side with iron toolsuntil recently. Although the stratigraphic distribution of artifacts matches what should beexpected in the archaeology of Pahi, the dates from the rockshelters are reserved fordiscussion because they do not conform to the pottery in discussion and, therefore, will bethe subject of further research.

Lithics

Analyzed artifacts included lithics and pottery in addition to faunal and floral remains.Rock art painting materials and iron-working remains were analyzed as well. Due to thelarge quantity of lithics recovered, subsampling was necessary. The lithics were classifiedbased on Mehlman's (1989) typology, with a few additions of new terminology forspecimens whose attributes did not conform to his classification. The analysis wasundertaken in two stages. In the first step, all 29,726 artifacts recovered from the fieldwere sorted into four main categories: shaped/retouched tools, cores, debitage, and non-flaked lithic artifacts. This quantity was considered sufficient for the purpose of this studyand, as such, lithic artifacts recovered from the survey were not included in the analysis.The second stage involved performing detailed analysis of a subsample of 4,852 artifacts(Table 4) representing 16.3 % of the total number recovered during excavation. If angularfragments (n=15,931) are not included, this sample includes 35.1 % of the total numberof tools, cores, flakes, and non-flaked artifacts (Table 4). Over 99 % of the lithic artifactsweremade out of quartz, while the rest were of basalt (n=5), chert (n=4), and obsidian (n=2).

All recovered tools and non-flaked stone artifacts were analyzed in detail, while coresand flakes were subsampled. The quantity of lithic artifacts recovered from a unit dictatedthe subsample size. All units with fewer than 200 lithic artifacts except Baura 1—unit 1had 100 % of cores and flakes/blades analyzed in detail. Units with several hundred coresand flakes/blades were subsampled. For example, 25 % of the cores and flakes/bladesfrom Baura 1—units 2, 3, and 4 and Lusangi 1—unit 1 was analyzed in detail, while 10%was examined fromMarkasi Lusangi 2—unit 3 (Table 4). However, unit 1 of Baura 1 wasan exception to this rule despite amassive quantity of cores and flakes/blades. This was thefirst unit to be analyzed, and judging from the amount of time involved in analyzing all

232 Afr Archaeol Rev (2013) 30:225–252

Tab

le3

Sum

maryof

C14

datesfrom

Baura

andLusangi

Sam

pleno.

Site,unit,

andlevel(depth)

Associatedfinds

Conventional

radiocarbon

age

Calibrated(B

Cand

AD)dates,2sigm

a,95

%probability

Beta17

6185

(AMS)

Baura

1,un

it1,

level5(83cm

)Lith

ics

2500±4

0BP

790–42

0BC

Beta17

6184

(AMS)

Baura

1,un

it2,

level3(39cm

)Lith

ics,daub

460±

40BP

AD14

10–148

0

Beta176192

(radiometric)

Baura

2,unit1,

level5(50cm

)Lith

ics,slag,tuyere

120±

50BP

AD16

60–195

0

Beta176191

(AMS)

Baura

3,unit1,

level1(10cm

)Lith

ics,pottery,slag,

tuyere,bone,land

snailshell

140±

50BP

AD16

60–195

0

Beta176186

(radiometric)

Lusangi

1,unit1,

level3(27cm

)(rockshelterP44)

Lith

ics,pottery,white

clay

1660±1

00BP

AD13

0–62

0

Beta176187

(AMS)

Lusangi

1,unit2,

level5(97cm

)Lith

ics,pottery,ostricheggshell

140±

40BP

AD16

60–195

0

Beta17

6188

(AMS)

MarkasiLusangi

2,un

it2,

level4(70cm

)Lith

ics,po

ttery,slag,bo

ne,daub

1030±4

0BP

AD96

0–10

40

Beta17

6190

(radiometric)

MarkasiLusangi

2,un

it3,

layer2(97cm

)(rockshelterP1)

Lith

ics,po

ttery,slag,iron

,tuyere,bo

ne,land

snail

shell,redochre,white

clay,bu

rntclay

4510±7

0BP

3370–293

0BC

Beta176193

(radiometric)

MarkasiLusangi

2,unit4,

level2(32cm

)Lith

ics,slag,tuyere,bone

760±

60BP

AD1180–130

0

Afr Archaeol Rev (2013) 30:225–252 233

cores and flakes/blades from this unit, it was decided that subsampling these elements wasthe most efficient option to be applied to the rest of the units.

Most shaped tools were recovered from Baura 1—units 1, 2, 3, and 4; Lusangi1—unit 1 (rockshelter P44); and Markasi Lusangi 2—unit 3 (rockshelter P1). Thelatter site produced over 99.6 % of the shaped tools recovered. Markasi Lusangi2—units 2 and 4 and Lusangi 3—unit 1 yielded one each, and the rest of the unitsyielded none. For that reason, only shaped tools from Baura 1—units 1, 2, 3, and 4,Lusangi 1—unit 1 (rockshelter P44), and Markasi Lusangi 2—unit 3 (rockshelter P1)will be discussed in detail (Tables 5 and 6, Fig. 5). For scrapers, the convex side form(20.5 %) dominated Pahi assemblages, while circular, nosed end, sundry end, side,notch, sundry combination, convex side, and concave combination forms were theleast frequent, each representing about 0.2 % (Table 5). In terms of backed pieces,crescents dominated, while triangles, trapeze, and angle-backed pieces were lessfrequent, each representing only 0.6 % (Table 6). Unifacial points were the onlyform of point recovered from the sites. Alternate edge points and bifacial points wereabsent.

Table 7 is a summary of shaped tools from Baura 1, Lusangi 1—unit 1, andMarkasi Lusangi 2—unit 3. Scrapers (66.6 %) were the most frequently recoveredshaped tools, followed by backed pieces (23.6 %), outils écaillés (8.1 %), points

Table 4 Lithic artifacts sampling strategy

Site Unit Number of artifacts recovered Number of artifacts sampled for detailed analysis

Tool Core Flake/blade NFS Tool Core Flake/blade NFS

B1 1 75 519 1,169 1 75 (100 %) 519 (100 %) 1,169 (100 %) 1 (100 %)

2 142 509 871 – 142 (100 %) 132 (25 %) 216 (25 %) –

3 130 458 862 2 130 (100 %) 115 (25 %) 215 (25 %) 2 (100 %)

4 9 89 169 – 9 (100 %) 23 (25 %) 43 (25 %) –

B2 1 – – 1 – – – 1 (100 %) –

B3 1 – 4 2 – – 4 (100 %) 2 (100 %) –

L1 1 170 523 1,587 – 170 (100 %) 131 (25 %) 397 (25 %) –

2 – 14 18 4 – 14 (100 %) 18 (100 %) 4 (100 %)

3 – 11 13 – – 11 (100 %) 13 (100 %) –

ML2 1 – 18 64 1 – 18 (100 %) 64 (100 %) 1 (100 %)

2 1 35 122 3 1 (100 %) 35 (100 %) 122 (100 %) 3 (100 %)

3 156 503 5,214 1 156 (100 %) 50 (10 %) 520 (10 %) 1 (100 %)

4 1 32 166 – 1 (100 %) 32 (100 %) 166 (100 %) –

L3 1 1 15 99 2 1 (100 %) 15 (100 %) 99 (100 %) 2 (100 %)

2 – – 2 – – – 2 (100 %) –

L4 1 – 3 4 – – 3 (100 %) 4 (100 %) –

Subtotal 685 2,733 10,363 14 685 1,102 3,051 14

Total 13,795 4,852 (35.1 %)

B1 Baura 1, B2 Baura 2, B3 Baura 3, L1 Lusangi 1, L3 Lusangi 3, L4 Lusangi 4, ML2 Markasi Lusangi 2,NFS non-flaked stone

234 Afr Archaeol Rev (2013) 30:225–252

Tab

le5

Frequency

ofscrapers

from

theLSA/IA

andLSA

levelsat

Baura

1,Lusangi

1(rockshelterP44),andMarkasiLusangi

2(rockshelterP1)

Scraper

type

Site

name

Baura

1,units

1,23,

and4

Lusangi

1,unit1(rockshelterP44)

MarkasiLusangi

2,unit3

(rockshelterP1)

Total

(allsites

andlevels)

Percent

Affiliated

cultu

ralassemblage

Affiliated

cultu

ralassemblage

Affiliated

cultu

ralassemblage

LSA/IA

LSA

LSA/IA

LSA

LSA/IA

LSA

Smallconvex

7(4.3)

–3(11.5)

9(9.1)

3(5.6)

2(9.5)

245.3

Convexend

27(16.5)

12(13.3)

5(19.2)

9(9.1)

10(18.5)

3(14.3)

6614.5

Convexdouble

end

1(0.6)

2(2.2)

3(11.5)

15(15.1)

10(18.5)

3(14.3)

347.5

Convexendandside

27(16.5)

23(25.6)

1(3.9)

25(25.3)

11(20.4)

–87

19.2

Circular

1(0.6)

––

––

–1

0.2

Nosed

end

1(0.6)

––

––

–1

0.2

Convexside

36(22.0)

18(20.0)

8(30.8)

15(15.1)

9(16.7)

7(33.3)

9320.5

Convexdouble

side

11(6.7)

19(21.1)

5(19.2)

25(25.3)

10(18.5)

6(28.6)

7616.7

Sundryend

3(1.8)

––

–1(1.8)

–4

0.9

Sundryendandside

1(0.6)

––

––

–1

0.2

Sundryside

12(7.3)

1(1.1)

–1(1.0)

––

143.1

Sundrydouble

side

3(1.8)

––

––

–3

0.7

Concave

22(13.4)

12(13.3)

1(3.9)

––

–35

7.7

Concavity

9(5.5)

2(2.2)

––

––

112.4

Notch

1(0.6)

––

––

–1

0.2

Sundrycombinatio

n1(0.6)

––

––

–1

0.2

Convexside

andconcavecombinatio

n1(0.6)

––

––

–1

0.2

Scraper

fragment

–1(1.1)

––

––

10.2

Total

164(100.0)

90(100.0)

26(100.0)

99(100.0)

54(100.0)

21(100.0)

454

100.0

Num

bers

inparenthesesarepercentages

Afr Archaeol Rev (2013) 30:225–252 235

Tab

le6

Frequency

ofbacked

pieces

from

theLSA/IA

andLSA

levelsat

Baura

1,Lusangi

1(rockshelterP44),andMarkasiLusangi

2(rockshelterP1)

Type

ofbacked

piece

Site

name

Baura

1,units

1,2,

3,and4

Lusangi

1,unit1(rockshelterP44)

MarkasiLusangi

2,unit3(rockshelterP1)

Total(allsites

andlevels)

Percent

Affiliated

cultu

ralassemblage

Affiliated

cultu

ralassemblage

Affiliated

cultu

ralassemblage

LSA/IA

LSA

LSA/IA

LSA

LSA/IA

LSA

Crescent

12(29.3)

10(45.5)

–21

(95.5)

46(67.6)

3(50.0)

9257

.1

Triangle

–1(4.5)

––

––

10.6

Trapeze

1(2.4)

––

––

–1

0.6

Curve

2(4.9)

2(9.1)

––

14(20.6)

1(16.6)

1911.8

Straight

2(4.9)

3(13.6)

1(50.0)

–2(2.9)

–8

5.0

Oblique

truncatio

n3(7.3)

––

–1(1.5)

1(16.6)

53.1

Ang

le–

1(4.5)

––

––

10.6

Divers

–2(9.1)

––

1(1.5)

–3

1.9

Awl/d

rill/percoir

13(31.7)

1(4.5)

1(50.0)

1(4.5)

3(4.4)

1(16.6)

2012.4

Con

cave

8(19.5)

2(9.1)

––

1(1.5)

–11

6.8

Total

41(100.0)

22(100

.0)

2(100

.0)

22(100

.0)

68(100.0)

6(100.0)

161

100.0

Num

bers

inparenthesesarepercentages

236 Afr Archaeol Rev (2013) 30:225–252

(1 %), and burins (0.7 %). Baura 1—units 1, 2, 3, and 4 produced the largest numberof shaped tools (n=356), followed by Lusangi 1—unit 1 (n=170), while MarkasiLusangi 2—unit 3 (n=156) produced the least.

Fig. 5 Pahi stone artifacts (all from excavated contexts): a–c small convex—Baura 1 and Lusangi 1; d convexend—Baura 1; e, f convex double end—Lusangi 1 and Markasi Lusangi 2; g, h, k–m crescents—Baura 1,Lusangi 1, and Markasi Lusangi 2; i trapeze—Baura 1; j triangle—Baura 1; n curve-backed piece—Baura 1; oadjacent platform—Lusangi 1; p multiple platform—Markasi Lusangi 2; q bipolar—Baura 1

Afr Archaeol Rev (2013) 30:225–252 237

Cores formed the second major category of Pahi lithic artifacts, and due to theirabundance they were well represented in every excavated unit (Tables 4 and 8, Fig. 5).Bipolar (50.9 %), diverse single platform (17.0 %), and opposed double platform

Table 7 Frequency summary of shaped tools

Type ofshaped tool

Baura 1, units 1,2, 3, and4

Lusangi 1, unit 1(rockshelter P44)

Markasi Lusangi 2, unit 3(rockshelter P1)

Total Percent

Scrapers 254 (71.4 %) 125 (73.5 %) 75 (48.1 %) 454 66.6

Backed pieces 63 (17.7 %) 24 (14.1 %) 74 (47.4 %) 161 23.6

Points 6 (1.7 %) 0 (0.0 %) 1 (0.6 %) 7 1.0

Burins 4 (1.1 %) 1 (0.6 %) 0 (0.0 %) 5 0.7

Outils écaillés 29 (8.1 %) 20 (11.8 %) 6 (3.9 %) 55 8.1

Total 356 (100.0 %) 170 (100.0 %) 156 (100.0 %) 682 100.0

Table 8 Frequency summary of cores types

Core type Site name

Baura 1, 2,and 3

Lusangi 1, 3,and 4

Markasi Lusangi 2 Total Percent

Part-peripheral core – 1 (0.6 %) – 1 0.1

Radial/biconical core – 1 (0.6 %) 1 (0.7 %) 2 0.2

Disk core 1 (0.1 %) – – 1 0.1

Levallois core 1 (0.1 %) – – 1 0.1

Pyramidal single platform core 1 (0.1 %) 1 (0.6 %) – 2 0.2

Divers single platform core 154 (19.4 %) 19 (10.9 %) 14 (10.4 %) 187 17.0

Single platform core scraper 1 (0.1 %) – – 1 0.1

Opposed double platform core 63 (7.9 %) 37 (21.3 %) 32 (23.7 %) 132 12

Opposed double platformcore scraper

1 (0.1 %) – – 1 0.1

Adjacent double platform core 67 (8.5 %) 10 (5.7 %) 7 (5.2 %) 84 7.6

Adjacent double platformcore scraper

3 (0.4 %) – 1 (0.7 %) 4 0.3

Multiple platform core 40 (5.0 %) 13 (7.5 %) 4 (3.0 %) 57 5.2

Platform/peripheral core 8 (1.0 %) – – 8 0.7

Platform/peripheral core/corescraper

– – – – –

Platform/bipolar core – – – – –

Platform/bipolar core/core scraper – – – – –

Bipolar/peripheral core – – – – –

Bipolar core 395 (49.8 %) 90 (51.7 %) 76 (56.3 %) 561 50.9

Bipolar core fragment 7 (0.9 %) – – 7 0.6

Amorphous core 51 (6.4 %) 2 (1.1 %) – 53 4.8

Total 793 (100.0 %) 174 (100.0 %) 135 (100.0 %) 1,102 100.0

238 Afr Archaeol Rev (2013) 30:225–252

(12.0 %) cores were the most frequent, while part-peripheral, disk, and Levallois coreswere least, each representing only 0.1 %. Core scrapers such as single platform, opposeddouble platform, adjacent double platform, platform/peripheral, and platform/bipolarwere rare in Pahi assemblages but are known to have been relatively more common atother central Tanzanian sites (Mehlman 1989).

According to Mehlman (1989), angular fragments, flakes, and blades were includedin the debitage category. As noted earlier, none of the angular fragments were analyzedin detail apart from simple counts. Flakes and blades (n=3,051) constituted 35.1% of thetotal excavated lithics (Table 4). Flakes constituted 90.2 %, while blades comprised9.8 %. The high frequency of flakes suggests that the Pahi LSA assemblages have beendominated by a flake rather than a blade industry (see also Masao 1979).

Only 14 non-flaked stones were recovered from Pahi project (Table 4). Four catego-ries of non-flaked stones were identified in the Pahi assemblages: hammerstone (four),edge anvil (two), pestle rubber (six), and sundry ground stone. All grinding and groundstones were recovered from IA levels, suggesting that they were involved in grindingactivities possibly brought about by the introduction of grain cultivation.

Ceramics

A clear characterization of Pahi pottery is not yet possible because of inadequate represen-tations of diagnostic sherds to enable reconstructions. Because of this problem, it was notpossible to establish the lower body profile and extent of the body covered with decorationsfor most vessels. However, from collected samples, it is apparent that most decorationscovered the region between shoulder and neck. Themost common techniques of decorationinvolved stamping, single impressions/stabbing (Fig. 6a, f–g), and incisions (Fig. 6e, h) androcking (Fig. 6b). Other techniques included fingernail impressions (Fig. 6c, d). In general,most vessels were made of fine clay tempered with fine sand, quartz, and mica. Thesetemper materials are similar to resources that were available locally, leading to thesuggestion that the pottery was locally made. Most of the pottery represented jars andbowls with wide openings and everted and straight rims. The vessels were probablyhandmade with the assistance of a paddle and anvil. Apart from decoration, final treatmentsof pottery included burnishing and slipping. Lack of adequate diagnostic pottery from theSTPs and excavated units made pottery seriation impossible. Given the work completed byLiesegang (1975) and Masao (1979) at Haubi and Kandaga, together with conclusionsreached by the current project, the Pahi pottery belongs to the Later Iron Age (LIA) period(but see Lane 2009 for EIA pottery from Haubi). This is demonstrated by the absence ofEIA decoration patterns such as fluted or beveled rims (Fig. 6). That the earliest pottery atPahi belongs to the LIA is supported by dates that fall around 1030±40 BP. The earliestevidence of pottery at Lusangi is associated with iron slag, suggesting that pottery and irontechnology were adopted at the same time.

Iron-Working Remains

Earliest evidence of iron-working at Pahi dates to 1030 years BP (Table 3). Theamount and sizes of slag fragments at Markasi Lusangi 2—unit 4 suggests that iron

Afr Archaeol Rev (2013) 30:225–252 239

may have been produced there on a large scale by 760 years BP. For example, at Baura2, a total of 7,014 pieces of slag (659 g) were collected, while at Baura 3, 4,364(2,397 g) and at Markasi Lusangi 2—unit 4, 9,751 (61,895 g) were collected. Thismeans, on average, each piece of slag at each of the sites weighs 0.1, 0.5, and 6.3 g,respectively (Kessy 2005). Although no standing furnace was recovered at MarkasiLusangi 2, based on the massive amount of slag recovered, there is little doubt thatthe furnace that produced them must have had a superstructure. Evidence indicatesthat bowl furnaces were employed at Baura by 120 and 140 BP (Fig. 4). Although theBaura furnaces looked similar, there were some notable distinctions. For example,one furnace had a ritual pit, while another did not. Furthermore, while the bowlfurnace at Baura 2 was a pit dug into the ground, the furnace at Baura 3 had a shallowpit dug in the ground but was supported by walls built above ground level.

One important feature shared by Baura furnaces is their orientation. All furnaceshave slag openings facing northwest (Fig. 4). This orientation is commonly found insouthwestern Tanzanian iron-smelting furnaces and has been associated with cosmo-logical representation, as well as other symbolic representation. In southwesternTanzania, the western direction is considered feminine. In the Fipa (Bantu speakers)tradition, Mapunda (2010: 158) notes the following:

Fig. 6 Pahi pottery: a Baura 1 (surface); b–d Lusangi 1 (surface); e Lusangi 2 unit 1, level 1; f Baura 3 unit1, level 1; g Lusangi 2 unit 1, level 2; h Lusangi 2 unit 1, level 2

240 Afr Archaeol Rev (2013) 30:225–252

… the western direction was selected both for location of smelting furnaces andthe palinyina [rake hole] because of its cultural/symbolic significance to theFipa and the strong relationship between iron smelting and human reproduction.The furnaces symbolized a woman in labor, “sitting” in the western (feminine)side of the termitary with the birth canal (palinyina) through which the newborn(bloom) would come also facing west.

Floral and Faunal Remains

Although soil samples were taken for flotation, floral remains were very rare. Therefore,information about the contribution of plants to the subsistence of the Pahi people remainsunknown. However, substantial faunal remains were recovered (Table 9). All identifiedspecies were recovered from IA levels. These included vervet monkey, giraffe, warthog,rock hyrax, and ostrich. Domesticated species were represented by cattle and chicken. Thedomesticated species were confined to the IA, suggesting that they were adopted togetherwith the iron-working technology.Masao (1979) observed similar patterns from IA levels,while the LSA levels indicated that only wild fauna were exploited.

Rock Painting Material

Two types of rock painting materials, red ochre and white clay, were recovered fromrockshelters P1 and P44. Red ochre and white clay were the primary raw materials

Table 9 Faunal identification

Level Mammal Vervet monkey 1

IA Giraffe 1

Bovidae Domestic cattle 2

Undermined Bovidae 29

Equidae Warthog 4

Undetermined Equidae 1

Rock hyrax 2

Undetermined mammal 3,728

Bird Chicken 14

Ostrich eggshell 7

Undetermined bone 4

Gastropod 71

Subtotal 3,864

LSA Gastropod 1

Mammal Undetermined Bovidae 2

Undetermined Mammal 88

Subtotal 91

Total 3,955

Afr Archaeol Rev (2013) 30:225–252 241

used to make red and white pigments for painting. As can be observed in Table 10,red ochre was distributed in both LSA and IA contexts, while white clay wasrestricted to IA levels. This sequence supports earlier assertions that red pigmentswere produced earlier than white ones, as well as that white paints were associatedwith IA culture (Anati 1996; Coulson and Campbell 2001; Kessy 2005; Masao 1979;Odner 1971; Phillipson 1976). Table 10 indicates that a wider diversity of materialsmay be present in IA levels. It also indicates that lithics and red ochre remainsoccurred in both LSA and IA levels, suggesting the continued use of these materialsin the IA.

Interpretation

The analysis indicates that the Pahi lithic artifacts can be associated with the LSA andwere produced mainly using a bipolar reduction technique. Figures 7 and 8 suggestthe presence of lithic workshops at all sites in both LSA and IA contexts. Thepresence of similar proportions of shaped tools, cores, and debitage in both LSAand IA assemblages suggests that there was little change in lithic technology betweenthe two traditions (see also Mehlman 1989). The lack of changes in lithic technologybetween the LSA and IA is demonstrated by the existence of similar types andrelative proportions of shaped tools and cores in both IA and LSA assemblages

Table 10 Summary of the distri-bution of materials

Industry Stratigraphicposition

Cultural remains

IA Upper Inorganics: lithics, pottery, slag, tuyeres,furnace, daub, glass, glass beads, redochre and white clay

Organics: domesticated and wild fauna

LSA Lower Inorganics: lithics and red ochre

Organics: undetermined mammal

0

10

20

30

40

50

60

70

80

Tools Cores Flakes/blades Angular fragments

Artifact type

Per

cen

tag

e

Baura1: Unit2, 3 & 4

Lusangi 1:Unit 1, 2 & 3

MarkasiLusangi 2:Unit 1, 2, 3 &4

Fig. 7 Major lithic artifact components, IA levels

242 Afr Archaeol Rev (2013) 30:225–252

(Figs. 9, 10, 11, and 12). Although lithic technology did not change significantlybetween the LSA and IA, there was a substantial increase in lithic productionimmediately before and at the initial introduction of IA culture, before consider-ably decreasing again (Figs. 13, 14, and 15). The increase in lithic productionobserved at the transition from LSA to IA was likely caused by more frequentuse of the sites due to the establishment of permanent IA agropastoralist settle-ments or by a population increase among LSA hunter-gatherers. Although it issuggested here that a population increase by hunter-gatherers could have trig-gered an increase in lithic production, the establishment of permanent settlementsis better supported by recovered field data. The establishment of permanentsettlements is attested to in the Pahi archaeological record by the appearance ofpottery, iron-working remains, herding of animals, and daub (Tables 9 and 10).The continuous gradual decrease in lithic artifact production in the latter partof the transition period was probably brought about by the slow adoption ofiron-working.

0

10

20

30

40

50

60

Tools Cores Flakes/blades Angular fragments

Artifact type

Per

cen

tag

e

Baura 1: Unit1, 2, & 3

Lusangi 1:Unit 1 & 3

MarkasiLusangi 2:Unit 1, 2, 3, &4

Fig. 8 Major lithic artifact components, LSA levels

0

5

10

15

20

25

30

35

40

45

Small

Con

vex

Conve

x End

Circula

r

Nosed

End

Conve

x Side

Sundry

End

Sundry

Side

Conca

ve

Conca

vity

Notch

Sundry

Com

binati

on

Conve

x/Con

cave

Com

binati

on

Cresc

ent

Triang

le

Trape

ze

Curve

Bac

ked

Straigh

t Bac

ked

Obliqu

e Tru

ncati

on

Angle

Backe

d

Backe

d Per

coir

Conca

ve B

acke

dPoin

t

Burin

Outil é

caillé

s

Tool type

Per

cen

tag

e

Baura 1:Unit 2, 3 &4

Lusangi 1:Unit 1(RockShelterP44)

MarkasiLusangi 2:Unit 3(RockShelter P1)

Fig. 9 Shaped tools from IA levels

Afr Archaeol Rev (2013) 30:225–252 243

Discussion

The Pahi Finds in Relation to Other Areas in Africa

To offer a better interpretive framework of the Pahi LSA and IA interactions, the Pahifindings are compared to those from other parts of Africa and inferences fromanthropological and archaeological examples of hunter-gatherer/agropastoralist inter-actions in other areas of the world are drawn (see also Kessy 2005). Recent inves-tigations indicate that the transition from LSA to IA in sub-Saharan Africa was morecomplex than previously thought (Karega-Munene 2002, 2003; Lane et al. 2007). Assuch, earlier theories that assumed replacement or displacement were the outcomes ofinteractions between autochthonous LSA hunter-gatherers and migrating IA Bantuagropastoralists in sub-Saharan Africa (e.g., Phillipson 2005) need reconsideration.

0

5

10

15

20

25

30

35

40

45

Small

Con

vex

Conve

x End

Circula

r

Nosed

End

Conve

x Side

Sundr

y End

Sundr

y Side

Conca

ve

Conca

vity

Notch

Sundr

y Com

binat

ion

Conve

x/Con

cave

Com

binat

ion

Cresc

ent

Triang

le

Trape

ze

Curve

Bac

ked

Straigh

t Bac

ked

Obliqu

e Tru

ncat

ion

Angle

Backe

d

Backe

d Per

coir

Conca

ve B

acke

dPoin

t

Burin

Outil é

caillé

s

Tool type

Per

cen

tag

eBaura 1:Unit 1, 2 &3

Lusangi 1:Unit 1(RockShelterP44)

MarkasiLusangi 2:Unit 3(RockShelter P1)

Fig. 10 Shaped tools from LSA levels

0

10

20

30

40

50

60

70

Part-p

eriph

eral

Radial

/bico

nical

Disc

Leva

llois

Pyram

idal

Divers

Single/sc

raper

Oppos

ed

Oppos

ed/scra

per

Adjace

nt

Adjace

nt/sc

rape

r

Multipl

e

Platfor

m perip

hera

l

Bipolar

Bipolar/f

ragm

ent

Amorp

hous

Core type

Per

cen

tag

e Baura 1 &3

Lusangi 1,3 & 4

MarkasiLusangi 2

Fig. 11 Cores from IA levels

244 Afr Archaeol Rev (2013) 30:225–252

Current research points to the occurrence of a slow independent adoption of IAelements (iron-working and agropastoralism) by autochthonous LSA hunter-gatherers without overdomination by IA agropastoralists. For example, archaeolog-ical data from Wadh Lang'o and Usenge in Kenya suggest continuity between theLSA and IA, a process that took a considerable time without replacement of autoch-thonous Stone Age populations. IA and LSA technologies continued to be practicedside by side for a long time with no significant differences in lithic assemblages fromdifferent stratigraphic contexts (Kusimba and Kusimba 2005; Lane et al. 2007). Thisobservation supports the position that the transition from the LSA to the IA was aslow process rather than a dramatic revolution. At the site of Usenge 3, the domes-tication of ovicaprines seems to have taken place during the Kansyore (LSA) traditionaround 1,000–1,500 years before the occurrence of Urewe (EIA) IA pottery.

It should be noted that similar types of archaeological sequences have beenobserved in many areas of Africa (Kwekason 2010). However, the difference betweenthe current interpretation and past research inferences lies with the methods of datarecovery and the type of anthropological approach used to interpret the findings(Phillipson 1976: 196). For example, in contrast to the conclusions made here, asimilar thick stratigraphic sequence at Makwe rockshelter in Zambia with a mixture

0

10

20

30

40

50

60

70

Part-p

eriph

eral

Radial

/bico

nical

Disc

Leva

llois

Pyram

idal

Divers

Single/

scra

per

Oppos

ed

Oppos

ed/sc

rape

r

Adjace

nt

Adjace

nt/sc

rape

r

Mult

iple

Platfo

rm p

eriph

eral

Bipolar

Bipolar

/frag

men

t

Amor

phou

s

Core type

Per

cen

tag

e

Baura 1

Lusangi 1,3 & 4

MarkasiLusangi 2

Fig. 12 Cores from LSA levels

0

5

10

15

20

25

30

35

1 2 3 4 5Level

Per

cen

tag

e

DiversityofShapedTools

ShapedTools

Cores

Flakes/Blades

LSA levelsLIA levels

Fig. 13 Baura 1, unit 2—stratigraphic frequency of artifacts by level

Afr Archaeol Rev (2013) 30:225–252 245

of IA and LSA artifacts that dates from AD 980±70 to recent times was interpreted torepresent activities that were practiced by two distinct traditions in alternatingoccupations (Phillipson 1976, 2005). In several areas of the world, scholars arenow raising concerns over the tendency for archaeologists to assume that metallur-gical and agropastoral technologies were superior to the Stone Age hunting-gatheringmode of subsistence. This traditional perception has led to misinterpretation ofarchaeological data (Kessy 2005). Young and Humphrey (1999), for example, notedthat many sites in England that yielded continual production of lithic artifacts throughthe Bronze and Iron Ages have been misinterpreted as an accidental stratigraphicmixture of artifacts. This misfortune is caused by the traditional belief that the StoneAge people would have automatically stopped the production of stone artifacts oncethey were exposed to metal-working. Young and Humphrey (1999), therefore, call forreevaluation of the sites that produced such evidence. Continuous use of lithic artifactsside by side with metal artifacts may have been related to several factors, such asproduction costs or preferences to use certain tools for specific activities (Kessy2005). At the site of Aksum in Ethiopia, for example, throughout the Aksumite period,people continued to produce and use lithic artifacts despite possessing a complex andsophisticated metal technology (Phillipson 2000a, b). This view is well supported byethnographic investigation. For example, studies among the Gurage, Arussi-Galla, andSidamo in central Ethiopia have indicated a preference for the use of obsidian tools in hide-scraping despite the availability of iron tools (Brandt 1996; Gallagher 1977). The

0

10

20

30

40

50

60

70

1 2 3 4 4a 4b 5Level

Per

cen

tag

e

Diversityofshapedtools

Shapedtools

Cores

Flakes/ blades

LSA levelsLIA levels

Fig. 14 Baura unit 3—stratigraphic frequency of artifacts by level

0

10

20

30

40

50

60

70

1 2 3

Level

Per

cen

tag

e

DiversityofShapedTools

ShapedTools

Cores

Flakes/Blades

LSA levelsLIA levels

Fig. 15 Markasi Lusangi 2, unit 3 (rockshelter P1)—stratigraphic frequency of artifacts by level

246 Afr Archaeol Rev (2013) 30:225–252

preference to use obsidian scrapers rather than metal ones is not related to the ubiquity ofraw materials but to its efficacy in carrying out hide-scraping (see Clark and Kurashina1981).

Searches for evidence of interaction between distinct populations require intensive andextensive examination of the sites where interaction took place. For example, excavationusing natural layers, as has been the case at Kamnama and the rockshelters of Thandwe,Makwe, and Kalemba (Phillipson 1976) of eastern Zambia, may prove less effective indata interpretation, particularly in cases where micro-level prehistoric cultural develop-ments exist. For example, excavation by natural layers alone may not effectively measurethe rate of accumulation. The comparative analysis presented in Figs. 7 through 15 waspossible because excavation relied on fine arbitrary levels within larger natural layers. AsVansina (1994–1995) and Kent (2002) have pointed out, there is a need to excavate moreforaging settlements fully and carefully, along with contemporary farming settlements, togain insights into interactions between the two groups. Such excavations should becombined with full-coverage survey of prospective areas to evaluate the nature of thelandscape use patterns of the interacting cultures. A strategy should be in place to make adistinction between site formation processes that result from displacement/elimination,assimilation, and acculturation/diffusion, as well as other factors that dictate site location,such as basic needs for a particular mode of production. This is why fine arbitrary-levelexcavations within natural levels were favored in this work. The stratigraphic sequences ofartifacts atMakwe rockshelter andWadh Lang'o, Usenge, and the Pahi sites do not supportthe theory of displacement or assimilation. This is because, in the case of assimilation ordisplacement, the traditions of LSA autochthonous peoples would not have had survivedvery long before being displaced or overshadowed by the new intruding culture.Therefore, LSA autochthonous groups at those sites must have continued occupying theirtraditional environment while slowly and selectively adopting some of the new elementsfrom their neighbors.

The Language Hurdle

Although the material remains from the Pahi excavations support acculturation ratherthan displacement or assimilation, how can one sort out the mechanisms that involvednonphysical aspects accompanying the acculturation process? For example, it has beenassumed that LSA autochthonous populations in sub-Saharan Africa were Khoisanspeakers. In contrast, the current Pahi people are Bantu speakers. If one assumes thatLSA autochthonous groups at Pahi were Khoisan speakers, one is obliged to postulatehow they acquired the Bantu language. This is a challenging question because there aredisagreements between archaeologists (Phillipson 1977, 2005) and linguists (Ehret1998; Vansina 1995) about how Bantu languages spread to sub-Saharan Africa.

It should be noted here that reconsideration of a language shift from Khoisan to Bantuby the Pahi LSA population does not imply that IA material culture elements must havespread together with language. The spread of the two elements might have taken separateroutes in time and space. The IA package model has received several critiques and haslittle support in modern scholarship (Phillipson 2005; Vansina 1994–1995). WhilePhillipson (2005) proposes that the displacement and assimilation models brought aboutby the Bantu migration explain the disappearance of Khoisan languages and the closedegree of intercomprehensibility observed in modern Bantu languages, Vansina (1995)

Afr Archaeol Rev (2013) 30:225–252 247

contends that diffusion is a more appropriate explanation. That is, it was not the by-product of a single large-scale migration, but the result of complex historical dynamicsthat involved the successive advance and reversal of individual languages over a time spanof millennia. The main agents that supported the dispersal included diffusion supplementedby small-scale migration, as original populations grew to form new settlements. Largesettlements practicing a sedentary way of life would have become centers of trade andsocial activities, attracting people from outlying areas and leading to the exchange oflanguages. In this scenario, autochthonous populationsmay have first become bilingual andthen over several generations lost their original language (Vansina 1995). In this view,technological superiority of IA traditions was not the main agent for the LSA culturalturnover, but instead the complex interactions associated with contact events.

This model is supported by several anthropological observations. For example, the so-called Pygmies of the Congo rainforest andWaata of Kenya are said to have interacted withBantu/Oromo-speaking farmers in a client relationship for centuries, ultimately replacingtheir indigenous languages with a Bantu/Oromo one (Phillipson 2005; Stiles 2001, 2006;Vansina 1990). This language shift was accompanied by intermarriage and the adoption ofcertain customs from the Bantu-speaking populations such as male circumcision (Coon1971; Vansina 1984). The Philippine Negritos lost their language after intensive interactionwith Austronesians sometime between 3000 and 1000 BP (Headland and Reid 1989).Despite this interaction and the adoption of the Austronesian language, Negritos continuedto practice hunting and gathering until modern times.

Trade and social interaction along the eastern African coast are suggested to havebeen the most influential factors in the spread of the Swahili language among differentcommunities (Nurse and Spear 1985). The establishment of caravan routes to theAfrican interior at the beginning of the nineteenth century extended this language toareas where it was not previously spoken (Whiteley 1969). Similarly, the Yaaku andWaata (Ariangulo) hunter-gatherers are said to have shifted to Laikipiak Maasai lan-guage, as well as an agropastoral economy not due to domination by Laikipiak Maasaibut as a result of social and economic interactions (Brenzinger 1992).

However, not all circumstances of interaction induce language shift (Brenzinger et al.1991; Brenzinger 1992). For example, the Oromo-speaking Waata (Brenzinger et al.1991; Brenzinger 1992), Sandawe (Brenzinger 1992), and Khoikhoi present cases insub-Saharan Africa where ethnic groups interacted with agropastoralists and adoptedtheir culture without shifting their indigenous languages (theWaata in this paragraph aredistinct from those mentioned in the preceding paragraph, see Brenzinger 1992 andStiles 2001, 2006). At the period of transition, these groups added only importantterminologies associated with the newly acquired economy from the donor culture.

The previously discussed examples suggest that causes for language shift betweenautochthonous LSA hunter-gatherers of Pahi and neighboring Bantu IA farmers maynever be completely understood. Multiple factors were likely involved depending onlocal situations (Mackey 1980). One has to recourse to evidence of language shiftsfrom other regions in order to propose a possible explanation. In general, the causesfor language shifts are multiple and interrelated and no cause can be singled out toexplain the loss of an ethnic tongue.

It is worth noting that new approaches to account for the spread of IA cultures in Sub-Saharan Africa are unfolding. The IA cultural package hypothesis has now been largelyreplaced by models where the spread of the so-called Bantu speakers, their language and

248 Afr Archaeol Rev (2013) 30:225–252

associated cultural elements constituted separate events that took place at different timesand places (for details on the ambiguity associated with Bantu migrationmodels, see Kessy2005). For example, in some areas along the eastern African coast, some communities seemto have practiced food production before the spread of iron-working (Chami 2004; Chamiand Kwekason 2003). The Bantu IA package model cannot be justified if the role of thePastoral Neolithic (PN) in peopling the area south of the Equator is considered. The PNpeople, supposedly Cushitic speakers, are suggested to have been in eastern Africa by thesecond millennium BC (Ehret 1998; Phillipson 2005; Robertshaw 1990), a date that impliesthat they appeared and introduced food production to eastern Africa well before their Bantucounterparts. Yet, their role as key players in the peopling and spread of food production toAfrica south of the equator has been overlooked compared to that of Bantu speakers. Thisbegs the question ofwhy the PN remained confined to a small region and did not experiencethe same degree of expansion as the Bantu speakers. It is logical to assume that the PNpeoples, with their mobile pastoral economy, should have been more widely distributedthan the Bantu speakers, who relied more on cultivation than herding (Sutton 1994–1995).

The Role of Genetic Studies

While the work by Tishkoff et al. (2009) on “the genetic structure and history ofAfricans and African Americans” marks a significant step in unraveling the history ofethnic movements and distribution of African populations, it falls short in its use ofanthropological approaches to studies of human interaction. Basic questions such aswhy genetic data indicate that the area south of the Equator is today predominantly“Bantu” instead of “Khoisan” are vaguely addressed. For example, the extensivedistribution of LSA industrial remains commonly attributed to Khoisan speakersraises the question of why they should remain so underrepresented in the moderngenetic pool in sub-Saharan Africa. Current anthropological and archaeologicalstudies on interactions between hunter-gatherers and agropastoralists do not supportelimination to have been the cause (see, for example, Brenzinger et al. 1991;Brenzinger 1992; Coon 1971; Headland and Reid 1989; Vansina 1990). Also, laterprehistoric (5000 years BP) studies on human movements and distribution in sub-Saharan Africa are built upon reliance on artifactual evidence rather than humanbiological remains. The use of such data, including their associated chronologicalevidence, to support genetic data may prove less useful because movement ofmaterial culture is not synonymous with human population movement. Again, thetendency to associate ancient material culture with modern ethnic groups has beenfound unreliable (Karega-Munene 2003; Lane 2004). The same applies to the use oflanguage spread. This is because there is disagreement between archaeologists andlinguistic anthropologists over the use of this aspect in tracing peoples' movements,particularly the use of glottochronology (Ehret 1998; Karega-Munene 2003;Phillipson 1977, 2005; Vansina 1995).

Conclusion

A date of 18,190 years BP from Kisese rockshelter marks the LSA transitional industry inKondoa, and by 3500 to 1000 years BP, the LSA proper was widespread in central

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Tanzania. Associated with the transition from the LSA to IAwas a change in rock art styleand subject matter, suggesting a modification in worldview (see Kessy 2011). Thetransition from LSA to IA in Pahi seems to have commenced around 1030 years BP andmay have began much earlier, as demonstrated by dates from Lusangi 1—unit 1. Thisprocess took place gradually and was accompanied by the conservation of lithic technol-ogy until recent times despite the introduction of iron-working and ceramics at the onset ofIA culture.

This assertion is supported by several lines of evidence coming from survey andexcavation results in the Pahi study area. First, the survey results indicate that bothLSA and IA remains were distributed homogeneously over the landscape, suggestinga continuous succession and possibly similar exploitation of the landscape by themakers of the two traditions. Secondly, all excavated areas demonstrate continuouscultural development with no breaks in stratigraphic sequences from LSA to IA.Thirdly, in most investigated areas, lithic technology was not abandoned abruptlyafter the introduction of iron-working. This implies that LSA people continued toexist in their traditional territory practicing some of their old traditions and, at thesame time, adopting new cultural elements from their IA neighbors. In sum, the Pahisurvey and excavation results suggest that the commonly held view that LSA hunter-gatherers were displaced or assimilated by incoming IA farming groups cannot beemployed as a universal explanation for the development of settled communities inSub-Saharan Africa. Instead, the Kondoa evidence and recent research in many areasof Africa (Kusimba and Kusimba 2005; Lane et al. 2007; Marean 1992) consideracculturation to have played a significant role as well.

Acknowledgments The production of this work would not have been possible without the contributions frommany quarters. I would like to thank Prof. Felix Chami and Prof. BertramMapunda of the Department of Historyand Archaeology, University of Dar es Salaam, as well as Prof. Catherine D'Andrea of the Department ofArchaeology, Simon Fraser University, for the critical review of my paper. I am also indebted to Mr. Said Kilindoof the University of Dar es Salaam for drawingmost of the diagrams. Special thanks go to the University of Dar esSalaam for funding the production of this work. I am so grateful to the Department of Antiquities, Ministry ofNatural Resources and Tourism, Tanzania for granting my research permit, as well as the people of Lusangi Pahiand Baura Pahi for being so generous during the whole period of research. Lastly, I would like to thank theanonymous reviewers for their helpful input and to acknowledge the assistance of Adria LaViolette in bringing thepublication of this paper to fruition.

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