Arubo 1: Early Palaeolithic in Luzon

Wilhelm G. Solheim II Foundation for Philippine Archaeology Online Reports No. 5, Sep 2005

Keywords: Philippines, Lower Palaeolithic, Acheulean, Lithic Technology, Chert, Handaxes, Curation, Movius line

The discovery and investigation of the Palaeolithic open site Arubo in the province of Nueva Ecija in Central Luzon in 2001 by the University of the Philippines’ Archaeological Studies Program has not only delivered a rather unique artefact assemblage, including a classic proto-handaxe, for Philippines’ earliest history but also raised discussions about its position in the Palaeolithic chronology and the consequences for the first arrival of humans in the archipelago. Arubo is at present the only known prehistoric site in the Philippines, where chert as raw material for lithic production was found, quarried and transformed into stone tools, while wear traces on the artefacts furthermore indicate that the people from Arubo used this site also as a camp. Considering the morphological elements of the Arubo artefacts, the site is of early Palaeolithic age. Its artefact assemblage is very different from the controversial “Cabalwanian” industry of Cagayan Valley in Northern Luzon. The presence of a bifacial technology and a selective core preparation in Arubo also contradicts the classic "chopper/chopping tool industries" scheme of Hallam Movius and adds a different aspect to the still ongoing discussions of the concept of the “Movius line” and the Southeast Asian Palaeolithic.

Early Palaeolithic sites have been reported from various Southeast Asian countries. However, their chronological and stratigraphic positions are mostly disputable, as is, at least partly, their artefact character. Although thousands of lithic artefacts have been recovered, our knowledge of the early stages of Mankind in Southeast Asia is still rather limited. One reason for that is certainly, that systematic archaeological research on the Palaeolithic was irregularly conducted due to various circumstances, including colonialism, wars and political unrest as well as sometimes a lack of interest by the responsible authorities (see Movius 1978; Loofs-Wissowa 1984:426-429). Nevertheless, fossil remains of Homo erectus found in Java (Koenigswald 1936a; Curtis 1995; Widianto 2001, and other authors), North Vietnam (Hoang Xuan Chinh et al. 1979; Le Trung Kha 1976) and Laos (Arambourg and Fromaget 1938) confirmed the presence of Early Man in Southeast Asia. With an absolute age of 1.81 ± 0.04 million years based on recently conducted Argon 40/Argon 39 isotope analysis, its earliest representative, the Mojokerto child from Sangiran, is even contemporaneous with the oldest Homo erectus findings in Africa (Curtis 1995: 44).

In the Philippines, a number of open sites and caves, respectively rockshelters have yielded prehistoric strata and artefacts, which can be characterized as Palaeolithic (Pawlik and Ronquillo, in prep.). They are mainly situated in Palawan Island and in the northern part of Philippines’ main island Luzon (Fig. 1).

Organized archaeological excavation and research have been undertaken since 1922. The leading archaeologist at this time until the 1950s in the Philippines, H. Otley Beyer has done most of the systematic archaeological work (Beyer 1947). Beyer conducted archaeological surveys, investigations and collecting tours in Luzon, Palawan and the Visayan Islands. A good share of these finds has been brought together by amateur collectors and even treasure-hunters (Solheim 2002: 1). Beyer’s initial work was continued in the 1950s, and since then until now by his former student, Wilhelm G. Solheim II. Since many years a celebrity in Southeast Asia’s Archaeology himself, Solheim has significantly contributed to the Prehistory of the Philippines. In the 1960s, Robert Fox, head of the Anthropology Division of the National Museum of the Philippines led a six-year archaeological research in Palawan where he focused mainly on the caves and rockshelters of Lipuun Point in the southern part of Palawan. Of the over one hundred recorded sites at Lipuun Point, the Tabon Cave is the best known. Excavated under the direction of Robert Fox from 1960 to 1967, it delivered Upper Palaeolithic industries and the oldest remains of Homo sapiens in the Philippines so far, a frontal and two mandibular fragments, the so-called Tabon Man (Fox 1970). These famous fossils were recently re-analysed after they have been kept in the National Museum vaults for more than 30 years. At the Institut de Paléontologie Humaine (IPH) in Paris, France, the age of the frontal was determined to be from 16500 ± 2000 B.P. by U/Th Gamma ray counting (Dizon 2000). Initially, an age of 22-24000 B.P. was assumed based on the conventional 14C date of an associated charcoal sample, dated at the University of California, Los Angeles Laboratory (Fox 1970: 40). Recently, the Tabon Cave is subject to re-excavation by the National Museum.

Besides Palawan, it is the island of Luzon and its northern part, the region of the Cagayan River that contributed to Philippines' Palaeolithic (Ronquillo 1982; Mijares 2002: 28-31). H. Otley Beyer’s collection of Pleistocene faunal remains attracted the attention of Ralph von Koenigswald who travelled in December 1957 to Cagayan and conducted a field survey. West of the city of Tueguegarao, between Rio Chico and Cagayan River is a wide plain landscape with Pleistocene deposits where Koenigswald collected fossils of Pleistocene mammals and stone artefacts at various places. He described them as archaic looking pebble tools, made of large Quartzite and sandstone pebbles. Some seem to have a handaxe-like form but were only unifacially modified. Koenigswald however, denied any similarity to unifacially retouched Sumatraliths of the Epipalaeolithic Hoabinhian tradition and suggested to call this assemblage “Cabalwanian” (Koenigswald 1958). Philippine archaeologists later adopted Koenigswald’s term „Cabalwanian” to name the lithic pebble and chopping tool industries of North Luzon in general (Fox and Peralta 1972).

Since 1971, the National Museum of the Philippines organized archaeological surveys in North Luzon. In 1976, the Cagayan Valley Pleistocene Project started as a joint venture of the National Museum, Iowa State University and the University of Iowa to investigate the sedimentation processes and determine the age of artefacts and faunal remains of that region. Until today, more than 100 open sites have been discovered. The lithic materials consisted mostly of simple unretouched flakes and few unifacially retouched pebble tools (Fox and Peralta 1972: 104-106; Peralta 1981: 7; Moser 2000: 132-133). This certainly proves the presence of prehistoric man in North Luzon. Although it was not possible to give certain dates for their appearance, the primitive-looking stone tools and the presence of Middle Pleistocene fauna conjured the image of Early Palaeolithic hunter-gatherers roaming in North Luzon. Still, no artefacts were discovered other than surface finds, which did not share any context with the stratified Pleistocene fauna (Shutler and Mathisen 1979: 113). A recent study of the lithic materials from Cagayan Valley raised some questions about the artefact character of some of the findings (Moser 2000: 134). Fox and Peralta’s determination of a secondary modification on 30% of all flaked artefacts could not be confirmed and even the distinction between artefact and geofact seemed to be problematic on a significant number of the findings.

In 1995, Mr. Jon Aves, grandson of Mr. Nicanor B. Aves, Sr., owner of a farmland called Arubo near the town of General Tinio, found there two stone tools together with pieces of fossilized wood. Mr. Aves reported the findings to the National Museum in Manila, which conducted a first inspection of the site in 1996 and suggested further investigation (Dizon 1996). The examination of the artefacts from Nueva Ecija identified one specimen as a typical proto-handaxe while the other one appeared as a large flake tool with a retouched tip (Pawlik, 2001). For the archaeology of the archipelago, this discovery was quite sensational, since no handaxes had been reported in the Philippines so far. With the support of the Fritz-Thyssen-Foundation, Düsseldorf, Germany it became possible to materialize a first archaeological investigation within the Summer Fieldschool Program of the Archaeological Studies Program of the University of the Philippines in April and May 2001. The fieldwork included an extensive survey, exploration and initial test excavations, which were conducted in cooperation with the National Museum of the Philippines. The investigated site was named "Arubo1" after the surrounding farmland. (Plate I).

Arubo belongs to the town proper of General Tinio in the province of Nueva Ecija, approximately 80 km north of Metro Manila (Fig.2). The site Arubo 1 is located north of the town of General Tinio and belongs to the district of Barangay Rio Chico. Its middle coordinates are 15°22'02.4"N, 121°05'52.5"E, elevated approximately 100m above mean Sea level.

The site is situated around a fishpond and is characterized by the presence of large boulders of chert and other rocks scattered on the present surface. Extensive diggings done by bulldozers brought these stones to the surface, after approximately 2-3 meter of topsoil has been removed to dig out the fishpond. The amount of earthenworks is indicated by the surrounding heaps, which still contain numerous chert boulders. The bulldozers removed the topsoil almost until the sandstone bedrock. In the area of Arubo are several more fishponds with chert boulders outcropping and the potential to find more lithic artefacts. Nowadays, most of the fishponds have been given up and are falling dry during the summer season. Also, Arubo 1 was in 2001 just a residual pond where no fishing was done anymore except for some gathering of snails and mussels.

As a part of the fieldwork in Arubo, exploration for site catchments was undertaken. The team was divided into three groups, equipped with GPS receivers and digital cameras to record potential sites with their field coordinates and a photographic documentation. The covered area was app. 2 x 2 km large. In total, nine sites with a similar appearance as Arubo 1 have been detected (and recorded as Arubo 2-10). All of them showed the same pattern of chert blocks outcropping at the surface and even a few flakes were found during the brief survey. The majority of the sites was also situated at former fishponds. This field survey, although it was rather limited and done within just two days, made clear that there is a high potential for more Palaeolithic field research and opened new perspectives for the future archaeological investigation of the Rio Chico area.

The main objective of the initial fieldworks at Arubo was to carry out a systematic prospection of the area where the stone tools have been found. For this purpose, a grid system was laid out, using a 10 square meter unit width. It was set up in north orientation and each grid node was marked with a wooden stake. Teams of 2-3 students were scanning each 10 square meter unit and plotting every artefact according to its x- and y-coordinates (PlateII). Additionally, every noticeable chert piece, nodule or boulder was recorded. Elevations of the whole area were taken and used to create a topographic map and a three-dimensional surface model of the site (Fig.3).

It was very soon observed that despite the disturbance created by bulldozers during the digging of the fishpond, two significant concentrations of chert, which were presumably associated with human activities can still be recognized (Fig. 4).

Based on the results of the systematic prospection, two 2x2m pits within the chert concentrations southwest of the fishpond were excavated by the participating ASP students (Plate III). Another two pits were opened by the National Museum team on the elevated area east of the fishpond, hoping to find an undisturbed stratigraphy, not affected by the bulldozing (Garong 2001: 6). Additionally, the elevated area beyond the chert concentrations in the south-western part of the site was chosen by the National Museum team to conduct Auger coring. It seemed however, that this area was more of a soil dump for the excavation of the fishpond (Garong 2001: 8). The excavations within the chert concentrations very soon reached the sandstone bedrock, indicating that the bulldozing left only little sediment around the pond (Fig. 5). The remaining stratigraphy at present consisted only of two layers of sediment under the grassy surface for the two pits inside the chert concentrations. Layer 1 is formed by a conglomerate of topsoil and very dense, clayish components. It is followed by Layer 2, composed of consolidated clayish sediment, already mixed with eroded sandstone from the underlying sandstone bedrock. This layer is already free of humous soil and has therefore not been significantly disturbed by the bulldozing.

From there, at least three artefacts were recovered presumably in situ, just above the sandstone base. All other findings were collected from the present surface. It is possible to expect an original position of the cultural materials under 2-3 m of sediment but at present, this cannot be supported by directly obtained data since a stratigraphy associated with the findings has been removed.

Two-hundred finds were collected during the prospection or found in the test pits. However, only 18 of them had certain characteristics of intentional manipulation, the others were mostly undeterminable cortical fragments and shattered pieces (Table 1). Identified were five cores, four core tools and nine flakes (Fig.6). Three flakes had been retouched. A morpho-metric and microscopic use-wear analysis of these artefacts was undertaken.

Category	Quantity
Shatter and undeterminable fragments	182
Cores	5
Core tools	2
Bifacial core tools	2
Cortex flakes	3
Flakes with dorsal ridges	3
Modified flakes	3

The silex raw material used for the artefacts is locally available. Although its contents of SiO² is currently unknown and therefore a mineralogical classification as chert or flint cannot be given at present (see Rottländer 1989: 9), the term “chert” is in the following used for this silex material, following the Philippine convention of the nomenclature. The exploration of the Arubo site and its vicinity showed that the whole area is scattered with large chert boulders of different variations in grain size, colour and texture (Plate IV). Based on the specific weight of chert (app. 2.5 kg/dm³) a weight of over 100 kg for the larger boulders is estimated. They seem to be more or less in situ (aside from the effects of the bulldozing) and might be the residual of the former limestone formation that covered this region during the Tertiary like the limestone massif of Peñablanca, app. 200 km north of Nueva Ecija (Ronquillo 1981: 2). Relicts of that limestone formation still exist around 10 km southeast of Arubo at Tarundong Bato, where the Rio Chico cuts through the limestone and forms a scenic landscape which is nowadays a popular weekend destination. 20 km south of Arubo begins the limestone formation of Bulacan. Its karst system with the historically important Biak na Bato caves is connected to the karst of Tarundong Bato. From Bulacan and Rizal province, already H. Otley Beyer reported "…five palaeolithic implements (of flint, chert and chalcedony) from the Rizal-Bulacan Collection. All from Middle or early Late Pleistocene sites in Rizal Province" (Beyer 1949: 5). The raw materials of those artefacts are similar to the ones from Arubo and might have the same origin. Unfortunately, the artefacts from Beyer's Rizal-Bulacan Collection were not available for a comparative analysis with the lithic from Arubo.

Due to its hardness and chemical resistance, the Arubo chert was mostly unharmed by the erosion of the sedimentary limestone but it shows indications of tectonic stress. No signs of a fluvial transport can be seen on the Arubo material, rounding and rolling marks are lacking. Also, fluvial beds are missing in the immediate locality of Arubo, except for a few artificial canals which served as drainage for the fishponds, but too small to carry the large and heavy chert boulders. The river bed of the Rio Chico is at its nearest c. 300 m away and 35-40 m lower than Arubo 1 and cannot serve as a carrier for the chert. Surveys conducted along the river bed revealed no chert pebbles at all. Although some artefacts can be typologically described as “pebble tools”, their nodules were not river pebbles. As of now, Arubo is the only known source of chert in primary location in the Philippines.

A total of 16 different varieties of chert were identified among the lithic materials. Predominant among the findings is a yellow-grey patinated and relatively fine-grained chert. The proto-handaxe and several other artefacts were made out of that material. The varieties include beside that yellow-grey chert also a pitted chert of coarse structure and even a porous, siliceous pseudo-tuff. Despite the presence of large boulders of fine grained homogenous material, even such rough and pitted sponge-like material was used for flaking. Aside from petrified wood fragments, no other materials have been detected, neither of organic nature, nor any earthenware.

Six unmodified or primary flakes have been found during the 2001 fieldschool. Among them are three cortex flakes and three unretouched flakes with dorsal ridges and negatives. The cortex flakes are significantly bigger in size than the other flakes. Although the number of artefacts is small, it might indicate the preparation of the large and locally available boulder cherts without much of a “smash-and-grab” style of initial flaking. None of the shattered pieces found during the prospection showed signs of further modification and/or use.

Despite their relatively small number, the artefacts from Arubo yielded a lot of information about the lithic technology performed at the site. Several cores have been found, all showing different preparation techniques and reduction sequences, ranging from simple circulating reduction (Plate V, d) to a horse-hoof-shaped core type (Plate V, b) similar to those found in Java and there related to the Pajitanian industry (Koenigswald 1936b), and of the Australian Core-Tool-and-Scraper-Tradition (Mulvaney & Kamminga 1999: 44-47.).

A core on a wedge-shaped fragment of a chert nodule resembles an artefact which was noted by the author among the assemblage from the Lang Vac site, Ngha An Province in Vietnam (Plate V, a). This is supposed to belong to the Son Vi culture of northern Vietnam. Son Vi was initially regarded as a Middle Palaeolithic open-site industry covering the period between 120,000 and 40,000 B.P., however based on typological criteria rather than absolute dating (Loofs-Wissowa 1984: 441). In the meantime, various cave sites with Son Vi assemblages under Hoabinhian layers have been discovered as well. Radiocarbon dates ranging from 20,000 to 10,000 B.P. place the Son Vi culture now in the later Upper Palaeolithic rather than a Middle Palaeolithic (Nguyen Khac Su 1994; Reinecke 1998: 61).

Very interesting is one of the stratified artefacts, a core on a large flake (Plate V, e). This relatively sophisticated artefact is made of a honey-coloured chert of similar texture as the material of the proto-handaxe. The rectangular, bar-shaped flake is at its distal part steeply domed. The butt seems to be from a striking platform on a natural joint plane. However, a visible dorsal reduction points towards a platform preparation. The flake has two dorsal ridges. One ridge had been partially removed by lateral flaking in the proximal area. Both lateral edges and the distal end are fully retouched. The ventral face served hereby as striking platform, since all negatives are on dorsal. The kind of retouch and the size and shape of the negatives indicate very obviously the intentional production of flakes. Subject to a use-wear analysis, this artefact is more likely a core than a used working tool. The dorsal face bears at least ten flake negatives.

A relatively flat ovoid pebble with a complete unifacial retouch seems to be Sumatralith-like (Plate V, c). But also this artefact, not possessing sharp edges, is more likely a core, for thin and larger flakes. Nevertheless, it shows a partial lateral retouch near its distal end which might indicate multi-functionality. But no recognizable use-wear has been detected.

Among the flakes from Arubo, a unifacially modified and slightly edge retouched flake resulted from an advanced core preparation (Plate VI, e; Fig. 7; see chapter Modified Flakes). Its truncated circular negatives on the dorsal face suggest even a levallois-like technique, although without the characteristic facetted platform remnant of a Levallois flake (“châpeau de gendarme”). In addition, before the intentional use of Levallois techniques in Arubo can be suggested, the related cores have to be found.

The most outstanding artefact is the bifacially worked proto-handaxe, which –found elsewhere- would certainly be regarded as typical for the Early Acheulean period (Pawlik 2001, 264-267). It is made of fine-grained chert, and possesses a smooth rind at the base. The size of the handaxe is: 150.0 mm length, up to 98.0 mm thick at its base and there up to 74.5 mm high. It weighs 958 grams (Plate VII). The handaxe is on its domed face A almost totally facial modified (Fig. 8). The plain face B is facially modified mainly in the distal part. Its right edge is completely retouched on face B. The retouching of the left edge created steep negatives on face A, with face B serving therefore as their striking platform. Two large negatives that probably were created to improve the handling of the tool have reduced the base on face B. From the base to the tip, the lateral view of the handaxe is perfectly wedge-shaped. Especially the distal part of the tool shows a complete edge retouch. A good control during the retouching of the edge is obvious and the lateral edges are at the same level. To reduce its end to form a tip, both lateral edges have been made slightly concave, producing an endscraper-like tip. The tip surely served as an individual functional area as well as at least the right lateral edge.

The rind at the base of the handaxe is smooth. Under the stereo-microscope, a polish-like gloss appears on some portions. This gloss does not seem to have resulted from post-depositional processes but can be interpreted as handling traces. Furthermore, glossy parts affect the edge of the rind and the adjoining retouched surface, and are therefore not just a natural appearance of the rind. It can be assumed that only long use has created such a surface alteration. Unlike the negative ridges on the tool faces, the lateral edges and the tip show visible rounding. This rounding resulted from the use of the handaxe. As a potential working material, plants, softwood or animal tissues can be considered. Phytolith-rich plants however, seem unlikely as contact material, since the typical phytolith gloss or „sickle gloss” is not present.

A very special feature is that the artefact shows different shades of patination. The patina of the original surface is heavier than that of the preparation negatives of the tool surfaces. Even less patinated than the large facial negatives are the smaller negatives, which seem to be the product of a rejuvenation of the lateral edges. The same can be observed on the row of small secondary negatives that form the semicircular tip. The very few and small scars from recent damages, show that the natural colour of the chert is light grey to yellow with a semi-opaque texture (see chapter Raw Material).

The fact that different stages of patination appear on different modification stages shows that the manufacture of the handaxe, its initial use, the resharpening of its lateral edges, and the endscraper-like retouching of its tip happened at very different times. Certainly, the resharpening and the last modification of the tip were done much later than the making of the tool. Therefore, the proto-handaxe must have been maintained by more than one craftsmen during two, or even three, different time periods. After a first period of use, the handaxe was picked up again, reworked, and re-used. The first reworking was done along the lateral edge while the second was done especially on the tip. Furthermore, the scarce non-intentional, post-depositional damages, and near absence of rounding in the facial ridges suggest that the tool has not been visibly affected by natural causes.

Other Core Tools (Plate VI)

Another remarkable artefact is a “pebble tool” with a thoroughly prepared tip on a larger flake-like fragmented chert nodule (Plate VI, c). Its fully retouched lateral edge shows very steep negatives almost at a 90° angle. The other lateral edge is partially retouched. That retouch continues towards a spatula-shaped tip. The tipped end is dorsal fully facial retouched but shows no modification on its ventral face. Donald Clark (1974: 81) described similar artefacts as "boulder flake tools". This type of a tipped pebble tool would as well fit into a Lower Palaeolithic. It is made of a rather different chert than the handaxe. Its middle-brown coloured cortex appears pitted with pores and looks almost like a sponge. However, the inner part shows fewer and smaller pores. The pebble tool has a length of 134.0 mm, width of 73.0 mm and is 50.0 mm high. The weight is 393 grams.

Plate VI(a) shows a large cleaver, a bifacially worked core tool made out of a coarse-grained and porous brown coloured chert. This material could be described as a siliceous pseudo-tuff. Despite its coarse structure, an excellent flaking control produced a straight and sharp semi-circular curved edge. The base of the tool is broken off. The fresh appearance of this break indicates a post-depositional cause, which happened probably during the bulldozing of the fishpond basin. It is therefore possible, that the complete tool was originally totally circular retouched. The domed “A-face” shows a stain-like greasy lustre what could be some kind of a patina. The length from the tip of the semi-circular edge to the break is 106.0 mm, its width is 120.0 mm and the thickness is 68.0 mm. This cleaver is another example for the bifacial technology of Arubo 1.

Plate VI(b) pictures a typical chopper, where the functional edge is created by a number of larger negatives on one side. This chopper is made of a fragmented chert nodule. One face, still bearing its rind, served as the striking platform for the chopping edge. This edge has a straight line with an edge angle of c. 60°. Unfortunately, almost half of the edge broke off leaving there a large negative. This break seems to be non-intentional, respectively post-depositional. Short secondary negatives with step and hinge terminations are recent. They show that the now medium-brown patinated chert was originally of greyish colour.

The remaining chopping edge has secondary scars as well. Mostly of short-wide shape, they also possess step terminations. They result from the use of this chopper, certainly on a harder material like wood or bones. The length, measured parallel to the functional edge, is 109.5 mm, width 53.0 mm and height 80.0 mm. The remaining length of the modified edge is 45.0 mm; it could have been over 90 mm before the damage occurred.

Plate VI(e) and Fig. 7 show a large flake, which has on the dorsal a complete facial retouch. It is made of medium-grained, quartzitic chert with yellow-greyish colour. Their circular distribution and the truncated proximal parts of the dorsal negatives point towards a Levallois-like flaking technique. However, it does not possess a facetted butt, characteristic for the Levallois technique. Interesting is a ventral reduction of the distal end. Obviously a core keel had been removed, perhaps for the purpose of a better handling of the tool.

Levallois technique is rather unique for the Southeast Asian Palaeolithic and has been reported only from the Upper Palaeolithic site Leang Burung 2 in Sulawesi, with radiocarbon dates between 19,000 and 31,000 B.P. (Glover 1981). However, Levallois points can appear accidentally from other core forms and must not necessarily result from a Levallois core (Hahn 1991: 97). So far, only one of the illustrated points from Leang Burung 2 shows the typical inverted Y-shape of the dorsal ridges (well illustrated in Loofs-Wissowa 1984: 445). But its “Y” shape is created by various small negatives instead of the typical short primary negative which classifies this flake rather as a Pseudo-Levallois point (Bordes 1950: 22; Kelley 1959: 9) than a Levallois point sensu strictu. The presence of Levallois cores would be a more reliable indicator for the use of Levallois technique, for Leang Burung 2 as well as for Arubo. The size of the artefact is: Length 90.1 mm, width 67.2 mm, height 37.0 mm. It weighs 181.0 grams.

One artefact appears as a flake with a scraper profile (Plate VI, f). It is made of a very inhomogenous chert with a conglomerate appearance. The chert’s colour is reddish brown with various intrusions. Its texture makes it difficult to determine the morphology and modification of this artefact. Clearly visible however, are two platform remnants, which are positioned perpendicular to each other. Both platforms are on natural breaks. Like other Arubo flaked artefacts, this scraper also derives from a double platform core. Apparently, the platform remnant opposite of the convexe-shaped edge resulted from the detachment of this flake. The convex edge has a scraper-like edge retouch created by irregular negatives. They are located on dorsal, where the distal end (following the above assumption) already possesses a natural scraper profile. It can hardly be distinguished whether those negatives are from an intentional modification or were created during use. Few shallow step negatives appear on the ventral side of the edge. Length (scraper edge is distal end) is 63.4 mm, width 79.6 mm and thickness 24.0 mm. Weight is 134.5 grams.

Another artefact even shows characteristics of a blade (Plate VI, d). Its length is 98.5 mm, width 25.4 mm and thickness 15.6 mm. It has a weight of 32.0 gr. This blade-like flake is therefore rather elongated and also slightly laterally curved with one convex and one concave edge. Lateral edges and dorsal ridges are parallel to each other. The chert has a relatively coarse and inhomogenous texture without visible Wallner lines or a developed bulb. Even the striking platform remnant cannot be identified with absolute certainty. A bipolar technology might have been applied on the original core. However, the presence of a dorsal reduction formed by a number of step-negatives indicates that the striking platform had been on the thinner and wider end. In addition, the opposite smaller end has a stronger bending, typical for distal ends. The slightly concave shaped edge has on its distal part (assuming the previous interpretation) some edge damage on the dorsal face. Short-wide hinge negatives are followed by larger scalar feather- and step-scars on a length of 25 mm. They can result from use, but also a post-depositional origin is possible, e.g. trampling. Dorsal reduction is as well a characteristic of blade core preparation. Nevertheless, to prove the use of a blade technology requires the presence of blade cores in the assemblage. Without them, blade technology remains speculative, as fascinating as this would be for the Arubo assemblage, with a potential presence of all major flaking techniques of the Palaeolithic Ages, as are unifacial and bifacial technigues, Levallois technique and blade production. On the other hand, a chronological characterization of Arubo would become more difficult if a true blade technology would be present. While the proto-handaxe and most other artefacts point towards a Lower Palaeolithic, blade production appears usually much later, especially in Southeast Asia. Still, accidentally created blade-like or quasi-levallois flakes occasionally come out in early Palaeolithic context as well.

The 2001 campaign at Arubo 1 delivered around 200 finds, made of locally available chert. 18 of them could be identified as stone tools, cores and flakes. Their morphological attributes and their technology certainly indicate a rather old age of the Palaeolithic site Arubo 1. This can be assumed not only because of their archaic typology but also according to the position of the excavated artefacts. While most artefacts were found during the surveys, a few were excavated with their position just above the sandstone bedrock already suggesting a Pleistocene age of Arubo 1. The nowadays weathered top of the sandstone could have been directly underneath the living floor. It is mostly free of humous coloration. This might indicate a drier and perhaps cooler climate, which is assumed during periods of glaciation of the northern hemisphere.

The people of Arubo discovered and used the lithic resources of this place for making stone tools. The presence of modified and curated tools as well as use traces on some of the artefacts indicate that Arubo was not just visited for raw material gathering and flintknapping, but also a place where Palaeolithic hunter-gatherers put up a camp. Yet, little is known about the Palaeoenvironment of this region. If this site –based on a rather conservative age estimation of the lithic findings- would be chronologically positioned in the Middle Pleistocene, a nowadays extinct megafauna with Elephas, Stegodon, Giant turtle and Rhinoceros would have accompanied the Palaeolithic hunter-gatherers of Arubo. The same has been suggested earlier for the pebble tool industries of Cagayan Valley (Koenigswald 1958; Fox & Peralta 1974). Those surface findings however, seem to share only the locality but not the stratigraphy with the Pleistocene fauna (see Shutler and Mathisen 1979). Although Arubo must currently regarded as an unstratified site as well, the typological and morphological spectrum can set the potential timeframe for the site much better than the amorphous and rather uncharacteristic material from Cagayan Valley for which recently their age and partly their artefact character as well has been questioned by various archaeologists (e.g. Bellwood 1985: 66; Moser 2001: 132-134) The presence of pebble or cobble tools alone is not necessary an indicator for a lower Palaeolithic, especially not in Southeast Asia. Such choppers and chopping tools as ad hoc- or expedient tools appear throughout the whole prehistory until the Holocene (Ronquillo 1981: 7)

Arubo and the "Southeast Asian Acheulean"

Unlike most Lower Palaeolithic sites in Southeast Asia, Arubo 1 delivered a manifold artefact assemblage, especially considering its relatively small number. It is significantly different from the stereotype "chopper/chopping tool industries" of Hallam Movius' scheme (Movius 1944). This brilliant simple scheme was at first based on finds from Java and Laos and separated the Old World in two archaeological regions, a western and an eastern, divided by a geographic boundary. Southeast Asia, India, Pakistan and China belonged to the Eastern Pebble or Chopping Tool Complex. The Arubo assemblage seems to jump across this border. The morphology of its artefacts, especially the bifacial tools, would very well fit into a “Western” Lower Palaeolithic. The Proto-handaxe is unique as artefact for the Philippines and even for Southeast Asia as well as its multiple uses and re-use was rarely observed on other Palaeolithic tools in the region. A rather old age can be assumed not only because of its archaic form but also according to the different stages of patination on the tool and the negative surfaces. Arubo presents unequivocal evidence that handaxes can be found beyond the so-called Movius line. Sixty years after its introduction, this borderline seems more and more a mere artificial mark without real cultural interconnection. Never being more than just a concept, repetitive citations in the literature of East Asia’s prehistory since then converted it into a widely accepted fact. However, it has never been proven as valid by comparative analysis of the numerous lower Palaeolithic sites and assemblages with modern standards of lithic analysis.

Bifacial tools like handaxes can be used in many ways and a bifacial modification alone does not mean a specific or exclusive use. The tool design including any secondary modifications but much more the intention of the individual tool maker/user is relevant for the use and function of the individual tool. Sergej Semenov, who perhaps deserves to be regarded as the initiator of Lithic Technology and Functional Analysis and who was a contemporary of Movius made it clear that the form of stone tools is induced by their function rather than their cultural association (Semenov 1964: 199-206). The making of stone tools usually does not serve any cultural purpose (although there might be certainly exceptions) it serves most of all the performing of mechanical activities as a part of human subsistence. So far, no use-wear analysis has proven the exclusive use of any working tool type for one specific purpose. On the contrary, use-wear analyses showed that especially handaxes were used as multipurpose tools (Keeley 1980; Müller-Beck & Albrecht 1994: 225-228; Veil et al. 1988: 260-261). Stone tools in general are not that specialized. Even arrowheads had been used for tasks other than projectile implements (Pawlik 1995: 128-130). A typology based observation like the alleged absence of certain forms like bifaces should be manifested under technological and functional aspects. This has not been the case and seems even hardly possible.

In China, a number of early Palaeolithic sites have been reported in recent years (e.g. Leng Jian and Shannon 2000; Schick and Dong Zhuan 1993; Xiang Anqiang 1990; Xie Guangmo, 1990, n.d.; Peng Shuling, n.d.). Despite the mostly limited quality of artefact illustrations in those reports, the occurrence of handaxes, proto-handaxes and other bifacial as well as unifacial artefacts is frequently observed. Even if Movius' dogma makes the authors sometimes hesitate to call them handaxes or proto-handaxes. Instead, rather complicated terms like "core with one bifacial leaf-shaped end" (Leng Jian and Shannon 2000: 23 and fig.6), thus labelling a classic proto-handaxe are invented. According to Yamei et al. (2000), bifacial technologies have reached South China around 800,000 years ago, associated with several handaxe sites in the Bose basin. Numerous handaxes and other bifacial forms are reported from the Korean Chongokni site with dates ranging from 100,000 to 600,000 years (Bae 1988; Schick and Dong Zhuan 1993: 32). During the Upper Palaeolithic Dyuktai Culture of Siberia, makers of bifacial artefacts did not hesitate to cross the Movius line and reached Northern and Northeast Asia. Bifacial traditions arrived with the first humans in North America via the now drowned subcontinent Beringia (Bering Strait) during the maximum stage of the Sartan/Wisconsin glaciation which correlates with the Middle-Late Wurmian (c. 22,000-14,000 B.P.) and connected Asia and America for about 8000 years. (Mochanov 1978; Hopkins 1982; Pawlik 1987).

The absence of a developed tool typology in Southeast Asian sites has also led to the conclusion, that lithic tradition in Southeast Asia can be categorized as an expedient technology, where stone tools were occasionally made for an immediate and single use. A main argument was the lacking of a qualitative appropriate raw material, i.e. cryptocrystalline chert and the availability of organic materials such as bamboo as substitutes (Mijares 2001: 138-139; Mijares 2002). Various overviews of Southeast Asian (including the Philippines) lithic sites however, show, that suitable raw materials like chert, Chalcedony, Jasper, Radiolarite, Quartzite and even Obsidian was widely available (e.g. Beyer 1949; Fox 1970; Moser 2001; Neri 2002). From the Epipalaeolithic to the Neolithic, formal tools as well as core preparation and blade technology appeared in Southeast Asia, like the Sumatraliths, edge-ground-tools and "short-axes" of the Hoabinhian, arrowheads and even geometric microliths in the Toalian Industry of Sulawesi (Mulvaney and Soejono 1970; Heekeren 1972), bifacial pebble tools from Gua Cha (Adi Haji Taha 1985) or the bifacial points in the Tingkayu sites of Sabah (Bellwood 1985: 41-43; Moser 2001: 125-126). Endscrapers have been reported from Laguinit Island, Samar, Philippines (Solheim 2002: 91) and a finely retouched sidescraper was recently excavated in Tabon Cave on Palawan Island, Philippines (Mijares, pers. comm.).

After archaeologists earlier postulated the existence of a "Holzindustrie” i.e. wood industry for Southeast Asia (Narr 1966: 133; Solheim 1969), the concept of a bamboo industry has gained some popularity in Eastern Asia since the late 1980s (see Pope 1989). As a substitute for a seemingly non-existing formal tool industry and especially replacing handaxes and other bifacial toolforms such as cleavers during the earlier Palaeolithic, bamboo seems to have become the solution to avoid calling the "primitive" Palaeolithic technology of Eastern Asia "backward" and a result of cultural stagnation (see Movius 1948).

On the other hand, there is at present no archaeological evidence for the use of bamboo as raw material for tools, nor have supporting archaeologists presented convincing arguments for potential bamboo tools able to replace heavy duty tools like handaxes and cleavers nor conducted comparative experiments of such bamboo tools with handaxes and other stone tools. The idea of Palaeolithic bamboo tools remains speculative until now. It goes too far to explain the lacking of formal stone tools with hypothetical tools made of bamboo, and even sounds like a mere excuse not to look deeper into a polyhedral problem. In this context one might also wonder, why the concept of a developed bone industry for Eastern Asia has been neglected until now, with few exceptions, like Johannes Moser, who postulated a bone industry for the Hoabinhian based on findings from Da Phuc and Hang Bung in Vietnam (Moser 2001: 34) and Carbonnel and Biberson for the Cambodian site of Phnom Loang (Carbonnel and Biberson 1968), even more since the existence of bone tools for the Palaeolithic is common knowledge.

The site Arubo 1 presents a picture different from the concepts mentioned above. Intentional tool preparation and selective tool use of its inhabitants can be assumed, based on the handaxe and other modified artefacts, but also due to the presence of core preparation. The manufacture of the Arubo artefacts was well planned and skillfully carried out, applying a variety of core and reduction techniques. Also, the maintenance of stone tools can be observed. Curation, as a concept contrary to expedient tool use (see Binford 1979), was performed by the people of Arubo. On the handaxe, curation is even observed as a special form along a larger time span. Probably not in a way Binford was having in mind, but nevertheless in the meaning of repeated maintenance by perhaps different generations of users. Such a “temporal curation” is rare to observe in lithic materials.

The new findings of Arubo show us again that still relatively little is known about the Palaeolithic in Southeast Asia. The lithic artefact analyses and comparative studies, which have been performed until now, are too few. The insufficiency in fundamental research is still obvious. It is therefore at present too early to postulate general conclusions for lithic technologies and technical behaviour in Southeast Asia and the Philippines, especially with regards to possible changes of concepts new discoveries like Arubo might bring along. However, it has become obvious, and the Arubo artefacts are adding to that, that after more than 50 years, the Movius Line has become obsolete and should no longer be treated by modern prehistorians like a sacred cow. We have to acknowledge that Palaeolithic bifacial tool technologies appear all over the world, including Southeast Asia, and even in case the Arubo assemblage remains a local facies.

Like the pebble tools of Cagayan Valley, most artefacts from Nueva Ecija are also unstratified findings. However, the presence of characteristic artefacts strongly suggests an early Palaeolithic stage, even if its age still needs to be rendered precise, if possible by absolute age determination. Additionally, the site and its artefacts were found in a “quasi-in-situ” position and not accumulated by alluvial deposits like in Cagayan Valley. Even the extensive excavation of the fishpond by heavy machines prior to the 2001 field school could not erase the original location of the site and the distribution of the artefacts.

In Ralph von Koenigswald’s initial 2-page article, published in Asian Perspectives 1958, he coined the term “Cabalwanian” for a supposed Philippines’ Lower Palaeolithic based on surface finds of rather amorphous pebble tool assemblages of questionable origin (Koenigswald 1958: 70). The presence of an identifiable early Palaeolithic bifacial tool technology and typology in Arubo and its “quasi-in-situ” situation--unlike the Cabalwanian sites--had initially led the present author to propose an “Acheulean” industry for Arubo. When the present author submitted a report about the fieldworks at Arubo during the IPPA meeting in 2002 in Taipei and after several fruitful discussions and exchange of information with IPPA 2002 participants, one participant expressed that this term is too “Eurocentric”--despite today’s rather basic definition of “Acheulean” as a Lower Palaeolithic stage with bifacial technology, especially handaxes and cleavers--and not applicable in Southeast Asia. The term “Acheulean”, however is already applied in East Asia, like in Korea or South China. This raises the question if and why exactly the region of Southeast Asia requires a separate terminology for basically the same artefact assemblages? Classifying the Arubo assemblage as “Acheulean-like” might appear “neutral” enough to be used within Southeast Asia. On the other hand, that term lacks a clear definition, yet and has furthermore no explicit relation to a certain region. However, nobody in the IPPA 2002 audience seemed to have any objections against the author’s proposal of using the term “Arubian” for the discussed artefact material. In the spirit of von Koenigswald, the proposition of the name “Arubian” for this assemblage with bifaces is hereby repeated.

Still, it is the author's opinion, that using the term Acheulean for Arubo is justified. In Palaeolithic technology, it should not be applicable anymore to tie technological and functional outcomes with regionalism and the author objects to such a simplistic and “regionalistic” argument but leaves it to the gentle reader to choose between Acheulean, Acheulean-like and Arubian.

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The 2001 Arubo fieldwork was an international joint venture of the University of the Philippines’ Archaeological Studies Program, the National Museum of the Philippines and the University of Tübingen, Institute for Palaeohistory and Quaternary Ecology and would neither have been successful nor possible without the engagement, expertise and support from the participating persons and supporting institutions. The author is grateful for the generous financial support the fieldschool received from the Fritz-Thyssen-Foundation, Cologne and the necessary technical equipment provided by the German Academic Exchange Service (DAAD). The author also wishes to thank the students and staff from the Archaeological Studies Program (ASP), the National Museum of the Philippines (NM) and the University of Tübingen (UT): Jun Castro (ASP), Abigail Delgado (ASP), Pamela Faylonas (ASP), Amee Garong (NM), Liane Giemsch (UT), Ric de Guzman (NM), Gregorio Magdaraog (ASP), Leee Neri (ASP), Dante Posadas (NM), Rey Santiago (NM), Sharon Teodosio (ASP) and Catherine Tulang (ASP). Special thanks go the distinguished archaeologists who supported the fieldschool and the author with their expertise: Prof. Dr. Wilhelm G. Solheim II, Prof. Wilfredo Ronquillo and Prof. Dr. Eusebio Z. Dizon from the U.P. Archaeological Studies Program, Prof. Dr. Johannes Moser from the German Archaeological Institute DAI and Prof. Dr. Hansjürgen Müller-Beck from the University of Tübingen. On behalf of all participants in the 2001 fieldworks at Arubo, the author thanks our hosts in General Tinio: Hon. Mr. and Mrs. Nicanor B. Aves, Sr., Mr. Nicanor “Jon” Aves III, Mrs. Adelaida “Ta Neneng” Aves, Hon. Mayor Virgilio Bote, Mrs. Milagros Flores and Mrs. Violeta Guevarra.