Economic and cultural prehistory of the Niger Delta.

Lacking the written records on which the historian relies, the prehistorian seeks to reconstruct the past through means of archaeological evidence.

   [O]bjects recovered from archaeological excavations ... bear the evidence
   of man's exploitation of his natural resources and utilization of those
   materials that serve to fulfill his aspirations. These may be objects of
   warfare, tools for hunting, procuring and preparing his food, for
   collecting and storing drinking water, ornaments for beautifying his body,
   objects to satisfy psychological and philosophical needs, ritual objects,
   and currency. These objects and their placement within a geographical
   context assume added importance if they are associated with materials such
   as charcoal and shell for radiometric dating; or objects of trade such as
   beads, copper manillas and cowrie shells for cross-cultural dating. Each
   object has its potential for supplying information on the disposition,
   habits, attitudes and technological progress of the people who lived on the
   site or in the area under study. (Anozie 1988:141)

The archaeologist must carefully select sites for investigation, rigorously record the locations of finds, and painstakingly analyze their relationships. It is through this careful attention to what may have been the household refuse of another era that the culture of a people can begin to be reconstructed, as well as their place of origin and patterns of migration. Often, however, physical artifacts cannot tell the "story" in its full complexity. Oral tradition, ethnographic studies, and environmental data can then complement or help to explicate the archaeologist's finds.

This essay will follow in a general way the course of the archaeologist's inquiry. First, we will briefly discuss the geology and environment of the Niger Delta--factors that are essential to site selection and the dating of artifacts. We will then examine the history of archaeology in the Delta, summarize the finds that have been discovered to date, and offer the results of radiometric testing of selected objects. Using these data in combination with the other forms of evidence noted above, we can then begin to consider conclusions that might be suggested regarding the region's economic and cultural prehistory.

Geology and Environment

The Niger Delta is the largest delta in Africa, covering approximately 75,000 square kilometers. Its formation as we know it today has been traced to the early Tertiary period, about 65 million years ago. During times of increased rainfall, the sea exceeded its natural boundaries and encroached on land. It retreated in subsequent periods of prolonged dryness, leaving deposits of sediments. It was through this alternating process that the Delta originated.

I. P. Okonny has indicated that "the near-radial disposition of the main delta rivers and their non-interrupted discharge into the sea classifies the Niger Delta as ... highly-constructive.... a delta that has been gradually building up and gaining more ground than it loses to erosion" (1988:23). As M. A. Sowunmi (1981) has noted, based on the work of J.R.C. Allen, "sediments entering the Niger Delta come from three independent sources; the Niger Benue drainage basins of rivers east of the delta, and drainage basins of rivers to the west probably including the Volta in Ghana." The maximum thickness of the detrital sediments of the Delta to date is approximately 8,000 meters (Hospers 1965). This subsurface has been divided into three layers: the Akata Formation, a shaley layer that extends from the sedimentary base; the Agbada Formation, which consists of alternating sandstone and shale and is the main oil reservoir sediment layer; and the Benin Formation, which is the sandy uppermost layer. The three layers extend across the entire Delta, and they all date from the Tertiary period (Okonny 1988:26). These detrital sediments have, however, been investigated archaeologically only to a depth of less than five meters in any part of the Niger Delta.

From an environmental standpoint, the Delta can be divided into three main zones: first, the freshwater swamps and forest on both sides of the Niger River; second, the saltwater mangrove swamps, which lie south of the freshwater swamps and are composed of mud and silt, covering approximately 10,360 square kilometers; and, last, the sandy beach ridges at the edge of the outer Delta (Udo 1978:227; Nzewunwa 1979:4; Derefaka 1991:16).

The History of Archaeological Investigation in the Niger Delta

The first organized archaeological fieldwork in the Delta was undertaken in December 1972 by a research team from the University of Ibadan composed of Professor E. J. Alagoa, Professor Thurstan Shaw, and Dr. E N. Anozie (Nzewunwa & Derefaka 1989:111-12). The team's initial reconnaissance tour included the sites of Onyoma, Nembe, Oruokolo, Kaiko, Ke, Brass, and Ogbolomabiri (Fig. 1).

As articulated by Alagoa, the investigations were aimed at determining "the earliest dates and locations of human settlement in the Niger Delta and its immediate hinterland [and] the relationships through migration, and diffusion of goods and ideas, between peoples and regions within the Delta and other parts of Nigeria" (Alagoa 1988a:18). The sites were selected from those named in oral tradition.

   [Many Delta] groups have either collective stories about their origin,
   their settlement, their migrations and development or the various units
   within each of these large groups have their individual stories about these
   aspects of their history. Each of these traditions is limited in content,
   in scope and in time depth. Some have various distortions, particularly
   about the sequence of settlements and migrations. (Nzewunwa & Derefaka
   1989:112)

Archaeological research in the Niger Delta has concentrated on the Ijo more than any other group, perhaps in part because they are the most populous group in the region and the fourth largest in Nigeria. Following the evaluation of possible sites, the University of Ibadan team decided to excavate test pits at Onyoma and Ke to study and date their cultural contents. With the exception of Ogoloma (see below), all sites excavated to date in the Delta have been test pits.

Excavations of the Eastern Delta

Excavations at Onyoma (an abandoned site) and Ke (which remains inhabited), near the sandy beach ridges bordering the Atlantic were carried out in April, May, and December of 1973, led by Anozie. In these two cases, the archaeological discoveries made through surface collection and excavation proved very similar. Located southeast of Nembe, Onyoma, like all the Eastern Delta sites, is a shell-midden site (i.e., its predominant content is the waste shells of shellfish). It was excavated at three points.

The majority of the finds were of fired clay in the form of whole vessels, potsherds, figurines (Fig. 2), and pipes. In all, the team found twenty-two miniature subspherical pots. Among the whole vessels were a decorated open bowl; a comparatively thick-walled bowl, possibly for use in grinding; a globular pot probably used to fetch water; and a terracotta human head wearing a hat incised with two vertical lines and crosshatching in between, perhaps to suggest a hat made of straw (Fig. 3). Raised mounds indicate eyes, and shallow depressions their pupils. Another protuberance outlined with two vertical incisions serves as a nose, and a horizontal slash suggests a mouth. Other artifacts included a glass bead, a spiral or coiled copper object, a human skeleton, a pierced canine tooth, oval-shaped pieces of chalk, and some bits of iron. Three charcoal and two shell samples were used for radiometric dating; the results suggest that the Onyoma site was occupied from 1275 to 1690 C.E.

At Ke, as at Onyoma, the finds at three points of excavation were predominantly of fired clay. The team also discovered more than eight hundred pieces of metal manillas (a form of European currency), terracotta mask heads (Fig. 4), clay molds, fragments of wine jars, some imported gin bottles, iron slags, a copper object, and fish and mammalian bones. A large, pierced Arca senilis shell was discovered at a depth of 220 centimeters (Fig. 5).

Six samples (four shell and two charcoal) taken from the Ke site were submitted to radiocarbon dating. Based on the results, two cultural layers were identified for Ke: a pre-European lower layer with dates ranging between 770 and 1270 C.E.; and an upper layer associated with manillas and gin bottles, dated to 1315-1686 C.E.

The research at Ogoloma, one of three settlements on Okrika Island, was led by Anozie in September 1974. The excavations, more extensive than those undertaken at Onyoma and Ke, yielded a large number of clay objects, including more than one hundred smoking pipes (Anozie 1988:184, pl. 6.8). Their stratigraphic distribution proved to be a useful time marker (Anozie 1988:150). Seventy-two percent of the pipes were locally made, and twenty-eight percent were European factory-made. Those of local manufacture predominated in the lower cultural layer, from about 320-340 centimeters up to 140-160 centimeters. The European pipes were most common in the upper cultural layer, from the surface to a depth of 120-140 centimeters. Six clay oil lamps, two terracotta animal figures (one of which appears complete), and some miniature clay pots resembling the twenty-two examples found at Onyoma were also recovered, as were some clay beads and three small clay cups. Other finds included fragments of a brass sword, a brass ring talisman, an axe head, an iron ball (perhaps a cannon ball), some copper bracelets, a small copper bell, ivory bangles, and perforated Arca senilis.

In addition, researchers recorded twenty-nine manillas at Ogoloma, mainly in the upper cultural layer. One of the manillas, made of copper, was of the king-size type (weighing 4,000 gm). Of the others, eighteen were of copper (approximately 80 gm) and ten were of iron (approximately 65 gm). The latter had rusted and were poorly preserved compared to the copper examples. The iron manillas were found at a depth of 160 centimeters in association with fragments of an iron chain, while the copper ones were recovered at depths ranging from 120 centimeters up to the surface. If one considers this fact together with the distribution of smoking pipes at Ogoloma, it is possible to conclude that some manillas were in use just before or coincident with the period of European colonialism (specifically the nineteenth century). Only the king-size manilla was decorated with discontinuous bands of crosshatching (Anozie 1988:175).

Three charcoal samples from Ogoloma submitted to radiocarbon analysis produced dates ranging between 1345 and 1850 C.E. The oldest sample came from the lower cultural layer at the site, while the other two nineteenth-century samples were drawn from the upper cultural layer.

Anozie headed excavations at the site of Saikiripogu in December 1975 and January 1976. After the original community was abandoned, it was then resettled and given the name Ewoama (New Town). Artifacts discovered here included potsherds, some tuyeres, a clay smoking-pipe, oval-shaped pieces of chalk, shells of a variety of saltwater shellfish, and mammalian bones. Two shell and two charcoal samples were radiocarbon-dated to 1135-1580 C.E. No European trade goods were recovered.

The last site to be excavated, by Nwanna Nzewunwa, in the saltwater Eastern Delta in the 1970s was Okochiri, also called Okopiri, near Okrika. A few people still inhabit the site today. According to oral tradition, this was the earliest mainland settlement of the Okrika people. The shell mounds here are among the oldest in the Niger Delta (Anozie, Nzewunwa, & Derefaka 1988:132). Although most of the finds were seashells, primarily Arca senilis or Tympanotonus fuscatus, the researchers also recovered a number of potsherds and some burnt clay fragments, palm kernels, a few iron fragments, and fish and mammalian bones. The four radiocarbon dates obtained for Okochiri range between 940 and 1425 C.E.

Finally, it should be noted that a very limited rescue excavation at Old Finima, near Bonny in the Eastern Delta, was recently carried out by Nzewunwa and A. A. Derefaka. This endeavor was necessitated by a project undertaken in the area by Liquefied Natural Gas (LNG), which threatened any possibility of future excavation. Analysis of these finds is now in progress.

Excavations of the Central Delta

After Derefaka carried out reconnaissance in 1979 in the Central Delta (delineated on the west by the Pennington River and on the east by the Nun), he and Nzewunwa undertook excavations at Agadagbabou (1980), Koroama (1981), and Isomobou (198:3). Pottery proved to be the most common find at all three of these sites.

At Agadagbabou, an abandoned site, about sixty-seven percent of the potsherds recovered were undecorated. Other finds included animal and fish bones, palm kernels, locally made clay smoking pipes, a clay pendant (Derefaka 1991:144), and two cylindrical glass beads with green, yellow, and red stripes. The archaeologists also collected J. J. W. Peters gin bottles at the surface some distance from the excavated area. Three charcoal samples were radiocarbon-dated to 1640-1730 C.E. (Derefaka 1991:135).

Nzewunwa and Derefaka excavated two mounds at Koroama, an inhabited site, in August of 1981. At the first of these, an industrial site where clay pots were fired, the primary artifacts were predictably pottery (Derefaka 1991:159-62). They also found a locally made pipe. The second mound, a refuse dump, yielded European factory-produced pipes (Derefaka 1991:163-75) in addition to snail shells, fish and mammalian bones, iron implements, gun flints, porcelain, glass beads, and pieces of J. J. W. Peters gin bottles. Radiocarbon dating of two charcoal samples produced a result of "modern," meaning that Koroama is no more than four hundred years old (Derefaka 1991:183).

At Isomobou, now abandoned, apart from pottery (Derefaka 1991:198-205) the finds included an iron spear tip, animal and fish bones, and burnt clay from hearths. Radiocarbon dating of seven samples suggests that the site was occupied between 1030 and 1480 C.E. (Derefaka 1991:217). Thus, of the three locations excavated in the Central Delta, Isomobou is the oldest and is perhaps contemporaneous with sites like Okochiri and Ke in the Eastern Delta.

Excavations of the Mainland

In addition to the work carried out in the Eastern and Central Delta, a few sites on the mainland in the Ogba and Ogoni areas have also been excavated. Nzewunwa describes the mainland zone of the Niger Delta as "an area of solid ground characterized by reduced forests following several years of continuous clearing by men in the course of agricultural activities. It is the home of the oil palm" (1988:40). Six sites--all of them abandoned settlements--were excavated in Ogbaland in 1984: Ikiri, Obrikom, Amah, Ahiawhor, Obigwe, and Omoku (Nzewunwa 1988:41-42). The Ogba sites were dated using a relatively new method, Electron Spin Resonance Spectroscopy (ESR).

At Ikiri, which according to oral tradition was the home of the first Oba of Ogbaland, finds included an iron tripod cooking stand, a knife-sharpening stone, pottery, a giant clay smoking-pipe of local manufacture, animal bones, and snail shells. Workers also recovered a large number of J. J. W. Peters gin bottles.

The main finds from Obrikom, the northernmost of the Ogba sites, comprised pottery, locally made clay pipes, animal bones, iron chain, iron slag, a Y-shaped copper pin, a copper chain, and palm kernels. Three bone samples from depths of 168 centimeters and 80 centimeters produced dates ranging between 3015 B.C.E. and 10 C.E.

The discoveries at Amah included pottery, clay pipes, and a broken copper bangle. No foreign trade goods were recovered. From Ahiawhor, also known as Akabuka, the principal finds were pottery, along with a pipe stem, iron knives, and gin bottles. At Obigwe, pottery again proved to be the predominant find, along with a pipe bowl, burnt kernels, and a broken copper bangle. No dates were obtained for these three sites.

At Umuagburu in Omoku, which according to oral tradition is the oldest settlement, workers found pottery, locally made pipes, animal bones, snail shells, knife and machete components, and ivory bangles. An ivory sample recovered at a depth of 50 centimeters was dated to about 2615 B.C.E. A second sample, this time of bone, from a depth of 30 centimeters, produced a date of about 1015 B.C.E. (Nzewunwa 1988:43).

It should be noted that radiocarbon dates are still required to corroborate the dates produced through ESR testing. Chronometric dates for Ahiawhor are essential, as it features in the oral traditions concerning the origin and migration of both the Ogba and Ekpeye peoples.

In 1985 Derefaka and Alagoa excavated Nama Sii on the mainland fringes of the Delta--located west of Sii Creek in the Ogoni (Kana) area (Fig. 6). The major finds consisted of periwinkle shells, pottery, a locally made clay pipe, and animal bones. No dates have yet been obtained for this site (Nzewunwa & Derefaka 1989:116).

Economic Prehistory

Considered in its widest sense, cultural prehistory comprehends the discussion of economic prehistory. For our present purposes, however--as we are seeking to demonstrate how links between material culture and the nonmaterial aspects of culture, such as ideas, aesthetics, and religious beliefs, may be established--it is useful to treat "economic prehistory" and "cultural prehistory" as separate entities.

Economic prehistory should be understood as an attempt to describe ways in which groups have sought to modify their physical environment to satisfy their basic needs for food and shelter. The discussion that follows will focus on the subsistence economy of the Ijo in the Niger Delta between the eighth and the eighteenth centuries of the common era. Some material objects known to have featured in this economy have not survived in the currently available archaeological record. This is why--apart from archaeology--ethnography, oral traditions, and environmental data serve as useful sources for reconstruction. Both the nature of resource integration at the local level and patterns of exchange at a wider level must be considered.

The procuring of food was an essential feature of Niger Delta economies during the period under discussion. In the saltwater mangrove swamps of the Eastern Delta (occupied by the Ijo subgroups of Okrika, Bonny, Kalabari, and Nembe), the economy consisted mainly of fishing and salt production; making pottery, thatch, basketry, cordage, and mats; and trading. Given the sensitive nature of the Delta ecology, understanding the nature of and relationships between the various aquatic and other resources in the immediate ecosystem were, and continue to be, crucial to their responsible exploitation and utilization. Religious and other cultural practices have in fact often evolved as a means to promote the regeneration of resources.

Shell middens reveal much about diet and food-gathering practices. They were used--for example, among the Okrika--usually near the waterfront and were essentially accumulations of household refuse assembled over long periods of time from neighboring compounds. In the excavations at Onyoma, Ke, Saikiripogu, Ogoloma, Okochiri, Nama Sii, and the limited rescue excavation at Old Finima, Nzewunwa sampled and analyzed shell middens (1988:200-11).

The middens contained various shellfish species (including cockles, periwinkles, whelks, oysters, and clams), pottery, animal and fish bones, charcoal, palm kernels, metal, objects, and fragments of burnt clay. Land mammals whose bones were excavated at Ogoloma include goats, cows, royal antelope, leopards, dogs, elephants, cats, and waterbuck. The bones of aquatic mammals have been identified as manatee and hippopotamus. A fish bone was determined to be that of an angler fish (Lophins piscatoris).

Nzewunwa correlated the mammalian bones from the Ogoloma site with the depths of the spit levels at which they were found (1988:207). In excavation unit IA, for example, at a depth of 80-100 centimeters (at level 5)--where European factory-made smoking pipes began to displace locally made versions--goat, cow, and antelope bones were recovered. Of the six goats identified between levels 1 and 21 (the latter ending at 420 cm), two came from levels 1 to 6, while four came from levels 10 to 21. Thus the first two date from the nineteenth century and the remaining four from a period between the fourteenth and about the eighteenth century. From between levels 23 and 24 (which ends at 480 cm), the highest bone weight appears, 1,630 grams, representing a royal antelope and a leopard. The presence of the manatee and the hippopotamus in the lower levels of the stratigraphic profile at the Ogoloma site is also significant. Whereas the goat, dog, cow, and cat are domesticated, the antelope, leopard, elephant, waterbuck, manatee, and hippopotamus must be hunted.

Fishing was also very important in the economies of the Eastern Delta Ijo groups. Although no fishing gear was recovered from archaeological excavations, ethnographic information and oral tradition clearly indicate that a variety of fishing methods were employed. Many of these did not change significantly during the period under consideration, although the materials used and the structure of some equipment evolved over time. Nets, traps, hooks, and fish poisons were all part of the repertoire. Similarly, various forms of traps and spears, as well as other equipment and methods, were used in hunting both on land and sea in the Delta during the period under review. The methods remained virtually the same until the Europeans introduced the flint gun.

The food sources discussed thus far provided protein, but they constituted only part of the diet of the Delta peoples, as indicated by ethnographic information. Indeed, while shellfish were a very important source of protein, for all their ubiquity they seem to have played a subsidiary role in the diet of the Ijo of the saltwater Eastern Delta. Even today, the various shellfish and crayfish are used more typically as condiments than as primary protein sources in the soup that is used to eat garri (cassava flour) or pounded yam. Thus, although differential preservation has made it impossible to recover vegetal remains during archaeological excavations in the Delta, data drawn from ethnography and oral traditions show that the bulk of the diet was composed of carbohydrates. If peoples in the Eastern Delta did not do much, if any, farming, how did they obtain the yams, cocoyams, plantains, cassava, fruits, and vegetables that were the basis of their diet?

This brings us to the significance of the freshwater Central Delta in the subsistence economy of the saltwater Eastern Delta peoples. Unlike the saltwater mangrove swamps, the freshwater swamps of the Central Delta contain very large islands, such as Wilberforce, with ample land for farming. Further, ethnographic evidence shows that species of yam, oil palm trees, and raffia palms grew wild in the Central Delta. For example, the Kolokuma and Gbarain who inhabit this area have been both fishermen and farmers and have long grown crops such as yams, various vegetables, and pepper. Introduced later, plantains, cocoyams, and cassava have also become staples. (1) Evidence from the excavations at Agadagbabou, Koroama, and Isomobou indicates that fishing, which was primarily pursued during the rainy season, was a more reliable and better developed source of protein than hunting in the traditional economies of the Central Delta Ijo. Farming appears to have been at least as important as fishing, if not even more so.

Oral sources reveal that commodities most abundant in the saltwater swamps and sandy beach regions--such things as salt, dried fish, and logs for firewood--were exchanged for tubers, grains, fruits, and meat from the freshwater swamps of the Central Delta and the mainland. This was more or less the situation when European traders arrived with goods that they were desirous of exchanging with the farmers of the mainland and freshwater swamps (see box, p. 80).

Cultural Prehistory

At present it is impossible to tell definitively when the Delta was first occupied by human beings. Except for Ogoloma, archaeological investigations to date have been limited to test pits. Furthermore, they have been widely scattered throughout the Delta. It is obvious that additional sites need to be investigated on a more extensive scale before precise dates can be determined.

Oral tradition and early European sources strongly suggest that it was the Ijo who first penetrated the Delta, probably entering the region at its apex or via the larger waterways. The eighth-century C.E. date procured through radiocarbon testing of samples found at Ke suggests that of the sites investigated thus far, Ke was the earliest to be inhabited in the Eastern Delta.

The artifacts discovered at the various sites reveal much about the life, customs, and religious beliefs of the early Delta peoples. Pottery, as has been earlier remarked, is the most prevalent of the finds across the sites investigated. Thus the Delta peoples possessed the technology for making vessels and figurines from clay for a variety of purposes, although they may have imported pottery items as well. The twenty-two small subspherical pots found at Onyoma and the similar pots found at Ogoloma resemble a type of pot called tamunobele, used "for appeasing the spirits of mothers whose children had died" (Anozie 1988:145), or for guarding against the possibility of child mortality. Decorated vessels found at Saikiripogu also suggest ritual or religious use, as do the clay figurines that have been unearthed. The tall hat decorated with crosshatching worn by the clay head found at Onyoma is reminiscent of headgear worn by the "Priest of the Creator" during ceremonies held at Okpoma in the Brass Local Government Area. Similarly, the small clay masks found at Ke resemble wooden masks, "especially the Opongi mask of the Kalabari" (Nzewunwa & Derefaka 1989:117). Other vessels and potsherds are decorated with animal figures that suggest a usage other than the merely pragmatic.

Another ubiquitous find is the smoking pipe--both the locally made version and the later European factory-made type. As Anozie has pointed out, "the habit of smoking, not necessarily tobacco, could be earlier than the smoking pipe or the arrival of European traders to the coast" (1988:159). Nzewunwa and Derefaka have also commented that "the people smoked from at least the fourteenth century a.d. but we still do not know for certain what they smoked. This habit was so important in the life of the people that they imported smoking pipes from the Europeans from the sixteenth century onwards" (1989:117).

The use of bodily ornament by early Delta inhabitants is evidenced by the pierced Arca senilis shells found at Ke and Ogoloma. Shells such as these were once worn as pendants by boys immediately following circumcision; they were used, too, as fishing weights. Pierced and strung together by youths, shells also served as ankle rattles for use in masquerades. Ivory and copper bangles and the relatively few beads discovered were probably marks of status. The pierced canine tooth resembles that worn as a pendant by priests even today in some communities.

At Onyoma a coiled copper object, described above, was found near the remains of a human jaw. This object, which resembles an iruka charm and which would have been worn by someone of substance, was probably buried with its owner. The small egg-shaped pieces of chalk recovered at Onyoma and Saikiripogu were very likely used by the priest of shrines to paint the body and face. The discovery of iron slag and the presence of metal objects used for a variety of purposes in addition to ornament indicate that Delta peoples were conversant with metalworking as well (see Peek & Nicklin 2002 for further information on the early Delta bronze industry).

From the foregoing, we can determine that the early peoples of the Delta possessed the appropriate skills and technologies to successfully exploit an area that must have been rich in game, fish, and, in the freshwater regions, wild crops (Nzewunwa & Derefaka 1989:118). They had a rich artistic tradition manifest in the production of figurines, miniature clay masks, decorated bowls, and bodily ornaments of metal and ivory. The figurines, pots, egg-shaped chalk, and a pierced canine tooth suggest elaborate religious practices that are substantiated by the ethnographic data.

With further systematic excavation of the Delta, we will some day be able to pinpoint the date when these early peoples settled the region, to chart their path of migration, to confirm their identity, and to expand considerably upon our present notions of their economy and belief systems. Unfortunately, a lack of funding and other problems have hampered archaeological research since the excavations of the 1970s and 1980s. Our work to date offers only a tantalizing glimpse of what yet may be discovered.

[This article was accepted for publication in September 2001.]

(1.) For additional information on the introduction of these crops, see Nzewunwa 1988:214 and Alagoa 1988b:241.

References cited

Alagoa, E. J. 1975. "Terra-cotta from the Niger Delta," Black Orpheus 3, 2/3:29-39.

Alagoa, E. J. 1988a. "Introduction," in The Early History of the Niger Delta, eds. E. J, Alagoa, F. N. Anozie, and N. Nzewunwa, pp. 1-20. Hamburg: Helmut Buske Verlag. In association with the University of Port Harcourt.

Alagoa, E. J. 1988b. "Conclusion," in The Early History of the Niger Delta, eds. E. J. Alagoa, F. N. Anozie, and N. Nzewunwa, pp. 231-48. Hamburg: Helmut Buske Verlag. In association with the University of Port Harcourt.

Anozie, F. N. 1988. "Cultural Prehistory in the Niger Delta," in The Early History of the Niger Delta, eds. E. J. Alagoa, F. N. Anozie, and N. Nzewunwa. Hamburg: Helmut Buske Verlag. In association with the University of Port Harcourt.

Anozie, F. N., N. Nzewunwa, and A. A. Derefaka. 1988. "Archaeological Fieldwork and Excavations in the Niger Delta," in The Early History of the Niger Delta, eds. E. J. Alagoa, F. N. Anozie, and N. Nzewunwa, pp. 121-39. Hamburg: Helmut Buske Verlag. In association with the University of Port Harcourt.

Derefaka, A.A. 1991. "Archaeology of the Central Niger Delta: Aspects of Central IJO Culture History." Ph.D. dissertation, University of Port Harcourt, Nigeria.

Hospers. J. 1965. "Gravity Field and Structure of the Niger Delta, Nigeria," Geological Soc. American Bull. 70:381-97.

Nzewunwa, N. 1979. "Aspects of Economy and Culture in the Prehistory of the Niger Delta." Ph.D. thesis, St. Johns College, Cambridge.

Nzewunwa, N. 1988. "Extending the Chronology of the Eastern Niger Delta," Nsukka Journal of the Humanities 3/4 (June/Dec.).

Nzewunwa, N. and A. A. Derefaka. 1989. "Prehistoric Developments," in Land and People of Nigeria: Rivers State, eds. E. J. Alagoa and T. N. Tamuno. Chap. 12. Port Harcourt: Riverside Publications.

Okonny, I. P. 1988. "The Historical Geology of the Niger Delta," in The Early History of the Niger Delta, eds. E. J. Alagoa, F. N. Anozie, and N. Nzewunwa, pp. 21-29. Hamburg: Helmut Buske Verlag. In association with the University of Port Harcourt.

Short, K. C., and A. J. Stauble. 1967. "Outline of the Geology of the Niger Delta," American Association of Petrol Geolo. Bull. 1:761-79.

Peek, Philip and Keith Nicklin. 2002. "Lower Niger Bronze Industries and the Archaeology of the Niger Delta," in Ways of the Rivers, ed. Martha Anderson and Philip Peek, pp. 39-59 Los Angeles: UCLA Fowler Museum of Cultural History.

Sowunmi, M.A. 1981. "Late Quatemary Environmental Changes in Nigeria," Pollen et Pores 23.

Udo, R. K. 1978. A Comprehensive Geography of West Africa. London: Heinemann.

Cross-Cultural Dating

In some of the sites that we have discussed, among them Ogoloma, Saikiripogu, and Ke, the stratigraphy reveals two clearly distinguishable cultural layers, namely that before and that after European contact. The former contain objects made locally, while the latter yield chinaware, square-faced gin bottles, copper manillas, and factory-made pipes in addition to locally manufactured goods.

Foreign objects can be an aid in cross-cultural dating when the dates of their importation are known. As Anozie has pointed out, such finds can give us the earliest possible date, or terminus post quem. Thus, "if manillas were found in an undisturbed layer ... and we know that manillas were first imported into the delta around 1450 a.d., then we can say confidently that the manilla layer cannot date before 1450 a.d." (Anozie 1988:158). Similarly, J. J. W. Peters gin bottles, which appear at several sites, were imported throughout the nineteenth century and into the twentieth. Alagoa has pointed out that this brand of gin was imported in cases of twelve bottles and became a "unit of accounting ... used in bridewealth payments and even in the payment of fines in the British colonial Native Courts" (Alagoa 1988b:246).

A variety of manillas. Metal alloy; largest 26.6cm (10.5") end to end. Manilla at upper right and central cluster of three: UCLA Fowler Museum of Cultural History (FMCH) X86.939, X86.948, X86.938, X86.941; all Gift of Steve Nelson. Two large manillas at left and cluster of three at lower right: FMCH X65.9010, X65.9017, X65.8264, X65.8266, X65.8265; alt Gift of the Wellcome Trust.

F.N. ANOZIE completed his doctorate at the University of Bordeaux. As a senior lecturer in archaeology at the University of Nigeria, Nsukka, he carried out several excavations in the Niger Delta and southeastern Nigeria.

A.A. DEREFAKA received his M.A. in archaeology from Indiana University and has taught at the University of Port Harcourt, Nigeria, focusing on the cultural archaeology of the Lower and Middle Niger.