 |
 |
 |
 |
 |
 |
RESEARCH METHODS (Part 1)
No stone technology will produce implements that are identical to each other in all attributes and features. Variation in the implements will arise from many different sources, these include the constraints imposed by the availability and physical properties of the raw material used. Variability is also a product of the reduction strategy adopted by the cultural group producing the implement in dealing with their environment.
The combination of bifacial and unifacial points are a unique feature of the Top End of Australia and yet they are considered as part of a pan-Australian tradition. This study removes stone points from this pan-Australian model and utilises them in a regional context. Therefore, only stone points were examined from each site with no attempt being made to include other stone implements and artefacts from each site.
Bamforth (1986) suggests that maintenance and recycling of stone implements should be seen as a response to raw material shortage. Binford (1977) theorised that technological response and implement variability relates to the organisational variations in implement manufacturing, necessary because of subsistence strategies and settlement patterns. Torrence (1989) relates curation to times of stress. By selecting a single implement type such as points, and spatially separated sites, it is possible to limit the influences on the technology.
Procedure
To enable comparisons with previous archaeological studies in the region it was decided to adopt a type category previously used such as points. Allen & Barton (1989) identify the use of accepted terminology as necessary for comprehension.
In any case analyses which do attempt to be rigorous and hold to a single system of classification produce results which are incomprehensible to the majority of Australian archaeologists, who are only comfortable with the popularly defined implement categories currently in use (Allen & Barton 1989: 52).
Implements were classified as points based on a combination of morphology and technology. In some cases, this was at variance from the implements defined as points in the previous studies throughout the region. Two easily identified types within the broad class of points are unifacial and bifacial.
To refine the accuracy of the study, broken points were excluded. Using broken points would entail an estimation process to reconstruct the unbroken point attributes. The sample size at all sites was large enough to justify the exclusion of the broken material for an increased level of data accuracy.
In order to determine the range of variation within an implement type, in this case points, it is necessary to describe the implement. A range of attributes and variables described the implements. Most of those used in this study were metric attributes, with a smaller number of non-metric attributes. These attributes were measured with a Vernier Calliper, as well as digital image capture and subsequent analysis by a computer software package. Digital image analysis was adopted because it offers faster and more accurate determination of implement attributes than normal techniques.
Class – Point
To explore the variability of points accurately, it is necessary to define the boundary of the class. Each of the previous archaeological studies in the region has defined the point class uniquely.
Flood (1967:36) classified points based on being "complete and unbroken, evidence of secondary working and the distal end should approximate to a pointed shape." It was the pointed distal end that she described as the "most difficult to apply".
Schrire (1982:38) describes points as " an implement that approximates in shape to an isosceles triangle, with a maximum length extending from the tip to the base". Unifacial and bifacial points are differentiated based on secondary working. Any degree of bifacial working excluded it from the unifacial category.
Barton and Allen (1989:55) provide little recorded classification criteria for the points excavated at Ngarradj Warde Djobkeng. The authors state that a "typical point would be leaf-shaped created by delicate flaking around its perimeter. The butt would be either semi-circular or angular in profile." No criteria is presented for distinguishing between unifacial and points.
Little has been done to define points beyond the imprecise boundaries outlined above. In this study, a point is defined as a retouched flake similar in shape to an isosceles triangle. The retouch may be present along one or both margins and may be restricted to the margins or extend beyond the central axis of the point. Both margins must converge at the distal end of the retouched flake (Hiscock 1997). The butt or proximal end may or may not exhibit retouch.
Type - Bifacial or Unifacial
There has been some discussion as to the definition of a unifacial or bifacial point. Mulvaney (1969) uses generic types and considers that if the bifacial trimming is restricted and functionally orientated then a technical bifacial point can be considered a unifacial point. Other researchers such as Flenniken & White (1985) define "true bifacial points", but also record points with a modified ventral surface and basal thinning as a unifacial point.
The use of generic typology necessitates a degree of subjective evaluation on the part of the examiner. Those proponents of generic typology have not established the extreme limits of the type. How much basal thinning or ventral face modification is required to change a unifacial point into a bifacial point? Is it the removal of half the basal thickness, three quarters or all? Does one scar, ten scars or fifty scars on the ventral face justify it still being called unifacial? Any reader may justifiably ask where the cut off limit is.
Crabtree (1972) defines bifacial as an "implement bearing flake scars on both faces" and unifacial as an "implement flaked on one surface only". To avoid the inherent difficulties with generic types, this strictly technical definition has been adopted for this study. All points were classified based on Crabtree’s strict definition of bifacial and unifacial retouch.
Attributes
To determine the morphology of the implements a series of metric, calculated and non-metric attributes were recorded for each implement.
Metric Attributes
In order to determine the morphology of the points and allow the degree of variation to be determined, a quantitative description of the point is required. In order to provide a quantitative description the following linear measurements were conducted on the unbroken implements.
|
| Figure 7 Measured attributes of implement. |
Length: maximum distance from the butt or platform to the tip (Figure 7).
Width: distance from lateral margin to lateral margin at the widest point of the implement, measured perpendicular to the long axis (Figure 7).
Thickness: distance between the ventral and dorsal face at the thickest point of the implement, perpendicular to the length measurement.
Butt to Width Line: distance from the width line to the butt, measured perpendicular from the mid-point of the width line (Figure 7).
Thickness of Butt: thickness of butt measured at mid point of butt.
Butt Width: width of proximal end whether retouched or not (Figure 7).
Weight: total weight of cleaned implement, measured to the nearest 0.1 gram.
Total Perimeter: distance measured around the total perimeter of the implement.
Surface Area: calculated plane surface area of the implement.
Calculated Attributes
Elongation Index: length divided by width.
Robustness Index: length divided by width multiplied by thickness.
Shape Index: deviation of implement shape from circular shape using the following formula:
 |
Base Length Proportion: distance from the width line to the butt, as a proportion of total length.
Area/Perimeter: surface area divided by the total perimeter.
Tip Angle: The approximate angle of the distal end between the margins. The head of any projectile point must penetrate the hide of the prey animal, and maximum achievable penetration is with a narrow tip angle. Too small a tip angle will produce a long weak point that is likely to fracture if it strikes either bone or the ground in the case of a miss. When the prey is struck at obliquely by a spear, the elastic rebound of the hide may deflect a point with a large tip angle (Fris-Hansen 1990:498). The tip angle was calculated with the following formula:
 |
Head Area: calculated head area of point using the following formula
 |
: Head Perimeter: calculated perimeter of head of point using the following formula:
 |
Efficiency Index: If stone points are seen as spear points, then a measure of the cutting efficiency of the point is potentially a valuable measure of both spatial and artefactual variability. Wounds that produce the largest damage to prey have a wide "wound track" surface area, and a higher probability of severing vital arteries and organs.
Dividing the head area by the head perimeter produces a measure of the potential disabling efficiency of the point (Fris-Hansen 1990:498).
 |
Non Metric Attributes
Butt/Platform: description of butt or platform (proximal end) i.e. scars, faceted or cortical. Differing platform surfaces have different advantages to the knapper (Hiscock 1986:49). Cortical platforms are unmodified surfaces and indicate minimum platform preparation. Platforms with several negative scars indicate some preparation of the platform by the knapper. Conchoidal and multiple scar platforms allow more control over the platform angle. However, their reduced frictional properties as compared to cortical surfaces, reduce the efficiency in force transference. In some instances, the level of retouch on the platform exceeds mere preparation in that the platform is totally removed.
Scars: the orientation of the dominant dorsal face scars. The majority of flake scars are perpendicular to an imaginary line between the tip and platform termed lateral (see Figure 8). Where the majority of flake scars are aligned parallel to an imaginary line between the tip and platform, it is termed longitudinal (Figure 8).
 |
| Figure 8 Alignment of dorsal surface scar. |
Dorsal: description of scars on the dorsal face. Where the majority of retouch scars extend no further than the mid-point between one margin and the tip to platform line it is termed marginal. Where the majority of retouch scars extend beyond the mid-point between the margin and a line drawn from the tip to the platform it is termed invasive (Figure 9).
 |
| Figure 9 Retouch scars |
Ventral: description of scars on the ventral face Where the majority of retouch scars extend no further than the mid-point between one margin and the tip to platform line it is termed marginal. Where the majority of retouch scars extend beyond the mid-point between the margin and a line drawn from the tip to the platform it is termed invasive (Figure 9).
Shape of Butt: description of butt (proximal end) of point i.e. round, square (Figure 10).
Part 2 - Determination of Attributes
Author: Wayne
Roddom, Dept. Archaeology and Anthropology
Feedback:
peter.hiscock@anu.edu.au .
Date Last Modified: 5-June 1998
URL:
http://artalpha.anu.edu.au/web/arc/aboutus/studs/research.htm