Bifaces and Retouched Flakes

Changes in the frequencies of bifaces and retouched flakes by excavation level, though relatively few in number, are one indicator of diachronic changes in production, and a notable pattern in these variables emerges from the 38 retouched flakes and 41 broken bifaces found in the workshop unit. The Q02-2u3 unit contained predominantly broken bifaces in level 3, and a statistically significant decline (a< .05) in relative prevalence of retouched flakes when comparing level 6 to level 3 in the workshop.

Figure 7-15. Retouched artifacts by Excavation Level.

As this is a workshop production site, not a consumption context, formal artifact classes are of limited utility in discerning changes in activities taking place. Notable changes appear to have occurred between level 4 and level 3. These inferences are reinforced by excavation data presented earlier (see section above "Q02-2u3 Descriptive Characteristics by Level"), where the high discard of cores in level 4 switched to a low discard of retouched flakes in level 3. Further detail into reduction trajectories by level requires investigating cores and flakes discarded at the workshop.

Cores

A very high number of cores were recovered from the 1x1 m workshop test unit (n = 352) and these cores were classified using the strict definition that the cores have not a single positive percussive feature. In the excavated sequence at Q02-2u3, cores show a distinct standardization in production between level 5 and level 4, a change in reduction strategy in level 3, and finally in the upper most levels 1 and 2 the pattern reverts to characteristics similar to that observed in the lowest levels.

Level		Obsidian		Rotations						Total
		Ob1	Ob2	0	1	2	3	4	5
1	No.	57	2	15	21	15	6	2	0	59
	% Lvl	96.6%	3.4%	25.4%	35.6%	25.4%	10.2%	3.4%	0%	100%
2	No.	46	3	18	20	4	6	1	0	49
	% Lvl	93.9%	6.1%	36.7%	40.8%	8.2%	12.2%	2.0%	0%	100%
3	No.	65	5	31	25	11	2	0	0	69
	% Lvl	92.9%	7.1%	44.9%	36.2%	15.9%	2.9%	0%	0%	100%
4	No.	90	4	25	31	24	10	3	0	93
	% Lvl	95.7%	4.3%	26.9%	33.3%	25.8%	10.8%	3.2%	.0%	100%
5	No.	53	1	26	17	7	3	0	0	53
	% Lvl	98.1%	1.9%	49.1%	32.1%	13.2%	5.7%	0%	0%	100%
6	No.	7	1	1	3	0	1	1	0	6
	% Lvl	87.5%	12.5%	16.7%	50.0%	.0%	16.7%	16.7%	0%	100%
7	No.	15	3	4	3	3	3	2	2	17
	% Lvl	83.3%	16.7%	23.5%	17.6%	17.6%	17.6%	11.8%	11.8%	100%
Total	No.	333	19	120	120	64	31	9	2	346
	% Lvl	94.6%	5.4%	34.7%	34.7%	18.5%	9.0%	2.6%	0.6%	100%

Table 7-17. Cores at Q02-2-u3 by excavation level showing counts and proportions of Ob1 and Ob2 material and rotations.

Figure 7-16. Q02-2-u3 Cores by Level showing changes length and weight.

These patterns can be summarized as follows. First, in the early levels, such as in basal level 7, large nodules were available and they were knapped more extensively, and then the cores were discarded while they were still relatively large in size, particularly if they were made of Ob2 obsidian. Rotations:In these earlier levels a high proportion of cores were rotated extensively, showing conservation behavior. Ob2 obsidian:three cores (16%) in level 7 contained heterogeneities. Some of these cores had a relatively high number of rotations, with three rotations on an Ob2 core in level 7 and there were four rotations on a lone Ob2 core from level 6. It appears that the presence of bubbles and other heterogeneities was a less significant deterrent to production in the early levels of workshop activity.

Subsequently characteristics of intensification and decline were observed in middle and upper levels of Q02-2u3. Discarded cores became increasingly more ovate through the intensification period of levels 5 through 3 (see Figure 7-16), where weight increased without a concurrent increase in length. Higher up, in level 2, the mean weight of cores plummeted by 15 grams. These changes in the morphology of discarded cores suggest that more detail on size variability among cores could shed light on the processes at work. These multivariate patterns can be illuminated through cluster analysis.

Cluster Analysis with Cores

Using the cluster analysis of cores from the workshop test unit, a few groupings of cores emerge from clustering on six variables. These more general groupings permit the examination of changes in core attributes in terms of types that reflect the underlying variability in the dataset.

Cluster analysis is a classification method that arranges a set of cases into clusters that are more similar to each other than they are to cases from other clusters (Aldenderfer 1982;Shennan 1997:234-258). The values from six ratio and scale variables of 334 complete obsidian cores from Q02-2-u3 workshop test unit were examined using hierarchical cluster analysis. Hierarchical clustering produces nested clusters with increasing variance within clusters as one ascends the cluster hierarchy.

Cores were clustered by first exploring different clustering methods on the Z scores of following measures: Weight, Length, Medial Width, Medial Thickness, Rotations, and Percent of Cortex. The four common hierarchical clustering methods: Single Linkage, Complete Linkage, Average Linkage and Ward's Method were conducted. This exploration revealed that regardless of the method selected, three cluster solutions were most commonly observed in the clustering agglomeration schedules. Three clusters generated by a Complete Linkage clustering solution provide the tightest clusters with measures on cores. Complete Linkage clustering, also referred to as "Maximum" and "Furthest-Neighbor" Method, is an approach where the dissimilarity between two groups is equal to the greatest dissimilarity between a member of cluster 1 and a member of cluster 2. Complete Linkage clustering tends to produce tight clusters of similar cases and the algorithm delays including new members in a cluster; furthermore, it does not tend to produce chaining.

	Function
	1	2
Weight (g)	.803*	.537
ThickMed (mm)	.723*	.109
% Cortex	.476*	-.366
Rotations	-.304	.654*
WidthMed (mm)	.193	.514*
Length (mm)	.264	.486*
* Largest absolute correlation between each variable and any discriminant function.

Table 7-18. Canonical discriminant function for Q02-2u3 Cores.

Clusters derived from cores are expressed in two discriminant functions shown in Table 7-18. This table shows the structure matrix for cores in order of size of correlation. Function 1 describes core sphericity using the Weight and Thickness measures, while Function 2 describes tabular shaped cores (Width and Length) with high Rotations.

Figure 7-17. Canonical discriminant chart for core clusters from Q02-2u3.

The variables were standardized using Z scores so that they had a mean of 0 and a standard deviation of 1, which has the result of regularizing measures like Percent Cortex (ranging from 0-100%) so that they cluster more effectively against the values of measures like Medial Thickness (ranging from 0.5 to 34cm). A description of the morphology of these three core clusters will be followed by an examination of the relative frequencies across levels.

Cores were clustered into three groups with low eigenvalues and relatively proportional counts in each cluster. An inspection of the clustering measures across the three groups revealed that the three clusters described three types of cores that were apparent during the lithic analysis.

Figure 7-18. Boxplots showing three clusters of Q02-2u3 cores with size measures. The tabular shape of C2 cores is apparent in their thinness relative to their length and width.

Characteristics of Three Core Clusters from Q02-2u3
	C1(n=226)	C2(n=56)	C3(n=52)
Size	Light, short, narrow cores that started on small nodules.	Mid-weight, and long and wide, but as thin as C1 cores.	Heavy, long, wide, and very thick. Ovate in shape. From larger nodules relatively unreduced.
Cortex and Rotations	Moderate amounts of cortex, moderate number of rotations on large number of cores.	Virtually no cortex and high number of rotations on cores.	High amounts of cortex, few rotations.
Ob2 Fraction	Few (n=10), or 4%.	Moderate (n = 8), 14%	None (n=0)
Comments	Smaller initial nodules.	Started on large nodules, and most heavily reduced.	Sampled but discarded early.

Table 7-19. Q02-2-u3 characteristics of three clusters from core attributes.

Did these clusters of cores result from intrinsic characteristics of three types of starting nodules, or are the clusters the result of reduction strategies and the particular reduction history of that core? C2 cores, for example, appear to have started as "tabular cores" but following some reduction they were discarded at the workshop despite being fairly large.

There is little correlation between clusters and attributes of the material such as Ob2 (hetereogeneous), cortex type, or color and banding characteristics. C1 and C2 cores separate easily into two groups: the C1 consisting of small cores and C2 with long, narrow cores that were heavily reduced. However, the cluster 3 (C3) cores are more enigmatic because they were discarded relatively early in the reduction sequence and these cores are evident throughout the sequence the workshop so the reason for their discard is not immediately obvious.

Figure 7-19. An example of a C1 core [L03-162.303], arrows indicate percussion.

Figure 7-20. An example of a C2 core [L03-162.305].

Figure 7-21. An example of a C3 core [L03-162.280] showing a small area of thin cortex.

Raw material availability and the opportunities for reduction in the particular reduction trajectory of a given core appear to determine the cluster in which a discarded core is categorized using this system. Following this logic, if the abundance beginning in Level 5 is due to quarrying work at the quarry pit, 600m up the slope, then additional large nodules would have become available from this quarry and with increased raw material availability, larger cores were discarded at the workshop during this time of abundance.

Figure 7-22. Clustered Cores from Q02-2u3 workshop test unit showing counts by level.

Changing proportions of these clusters of cores between levels, particularly between levels 5 and 2, suggests that there was a changing availability of raw material. A distinctive pattern emerges that centers on level 4 as the probable apex of production of large flake blanks for export from the workshop. In level 4 there are a relatively large number of C2 cores with 3 or 4 rotations and yet they are over 50mm long and appear to have been discarded far earlier than would have occurred in other levels in the workshop. The varying counts and weights of these clusters evident in Figure 7-22 show a peak in large, cortical cores (C3) in level 5 that are replaced by heavily reduced tabular cores (C2) in level 4, and finally both groups give way to an increase in counts of small, moderately retouched cores (C1) in level 3.

The presence of quantities of C2 cores in Level 4 is particularly intriguing because the discard of cores with little cortex (and thus heavily worked), yet still evidently long and tabular, suggests that very large cores were abundant in this phase. By level 3 the C2 cores were replaced by the smaller C1 cores that are moderately reduced, which are taken to mean that large cores were no longer available and surpluses of large cores remaining in the system from earlier times had been consumed. The most parsimonious explanation for this abundance of large, tabular C2 cores in level 4 is that a new source of obsidian were being exposed through labor investment in quarrying in the vicinity of the workshop. A¹⁴C date from level 4 calibrates to between 1500 - 1380 BCE, or the end of the Early Formative, precisely when obsidian is most abundant at consumption sites like Qillqatani (discussed in Section 3.4.2).

Cores compared with Cortical Flakes

Measuring changes in the maximum size of obsidian nodules over time is complicated by the fact that cores become smaller through use. If cores are the subject of export then one can compare the maximum length of early stage reduction cortical flakes (where dorsal cortex ? 50%) with the maximum length of cores as an indicator of the maximum possible size of cores during a given period. However, if large flake blanks are being further reduced and/or exported then large flakes will not be discarded at the workshop and core length may exceed cortical flake length.

Figure 7-23. Q02-u3: Graph showing means of complete cores and cortical flakes.

First, consider the mean values of cores and cortical flakes across excavation levels in their aggregate. The differences between excavation levels using the measures displayed in Figure 7-23 are extremely significant using an ANOVA test of variance.

Tech. Class	Measure	df	F	Signif.
Cores	Length (mm)	6	2.589	.018*
	# Rotations	6	6.241	.000***
	% Cortex	6	3.834	.001***
Flakes	Length (mm)	6	7.168	.000***
	Width (mm)	6	4.529	.000***
	Weight (g)	6	5.968	.000***

Table 7-20. Q02-2u3: ANOVA on complete cores and flakes with at least 50% dorsal cortex.

In Table 7-20 the observed differences in means are extremely significant ( p? .001) except for the means of core lengths which are significant ( p< .018), confirming that the variability presented in Figure 7-23 is meaningful. The variability in means suggests that specific measures should be investigated in more detail across excavation levels. Changes in means by level on complete cores and cortical flakes as a whole are shown in Figure 7-23 where notable fluctuations on a variety of independent measures that converge around level 4 can be observed.

These differences by level show the relationship between discarded large cores and the cortical flakes that were struck from them. The measures Flake Lengths and Core Lengths show that mean core lengths exceed flake lengths by about 10 cm. The relative decrease of long cortical flakes in level 3, despite the continued availability of long cores, suggests that there was an export of long, heavily reduced cores and large flakes; artifacts that were probably exported as flake blanks.

The absence of cortex on smaller flakes is useful for discriminating advanced reduction flakes from small flakes that simply derived from small cores. Small flakes are abundant in level 3 (as will be shown later below in Figure 7-24) and means in non-normal distributions are sensitive to skewing. One may ask "is the sheer number of smaller flakes in level 3 from more advanced reduction activities, as demonstrated by the presence of broken bifaces in level 3 (discussed earlier), skewing the mean and lowering the mean length of flakes?"

The Pearson's r correlation coefficient between Length and the Percentage Cortex variables is strong on complete flakes from both level 3 and 4, but it is extremely strong in level 4. In level 3 there is a strong correlation between Length (X) and Percentage of Dorsal Cortex (Y) ( r= .203, p= .001, Y = .79X + 19.06). In level 4 the correlation between Length (X) and Cortex (Y) is extremely strong ( r= .330, p= <.0005, Y = 1.16X + 22.89). Evidently flakes got smaller in level 3 even when they contained significant dorsal cortex coverage, supporting the argument that larger cores were less available in level 3 than they were in preceding levels.

These changes in core morphology support earlier patterns that were observed in the distribution of retouched flakes and bifaces in levels 4 and 3 (see Figure 7-15). Recall that the retouched flakes that were prevalent in level 4 are largely replaced by bifaces in level 3 when smaller cores are dominant and procurement of large, tabular C2 cluster cores appears to be curtailed. These data from cores corroborate the data from bifaces and retouched flakes. Further evidence comes from a detailed examination of the last group of artifacts from the Q02-2u3 test unit to consider, the most well-represented group at the workshop: unretouched complete flakes.

Complete Flakes

Measures on 1063 complete obsidian flakes from the obsidian workshop test unit provides evidence of changing activities through time that support the observations made on cores and retouched artifacts. Flakes will be examined first through the mean values on their numeric attributes.

Figure 7-24. Q02-2u3: Graph showing means of measures on complete obsidian flakes.

The mean values of flake measures length, average width, average thickness, weight, platform width, platform thickness, percentage of dorsal cortex, and count of rotations were presented. The average width and average thickness variables were calculated by averaging the Proximal, Medial, and Distal measures for Width and Thickness on each flake.

Measure	df	F	Sigif.
Length (mm)	6	9.392	.000***
WidthAve (mm)	6	7.290	.000***
ThickAve (mm)	6	9.431	.000***
PlatWidth (mm)	6	2.344	.030*
PlatThickness (mm)	6	2.358	.029*
Weight (g)	6	7.707	.000***
% Cortex	6	18.819	.000***
# Rotations	6	2.914	.008***

Table 7-21. Q02-2u3: ANOVA on measures from complete flakes.

The observed differences in means are extremely significant ( p? .001) except for the means of platform width and platform thickness, which are merely significant ( p< .05). While mean values across levels are highly subject to skewing due to overrepresentation by the numerous small flake categories, the data in Figure 7-24 demonstrate that the large sizes associated with level 4 cores discussed previously are repeated in the flakes from level 4.

In Figure 7-24, the percent cortex variable shows a notable spike in level 5 but this variable should be considered in conjunction with the weight variable because by weight and size these highly cortical flakes are relatively small. Looking at the percent cortex in level 7, in contrast, one can see that there is little cortex and a mean weight of 8 grams indicating relative abundance and relatively wasteful reduction at the workshop. These large level 7 flakes appear to have come from large cores because they are comparably heavy, wide, and thick, and the flakes are not very cortical. This changes rapidly in level 6 as mean weight goes down despite a slight increase in corticality. The number of rotations similarly points to more efficient decortication in level 5 with thinner, shorter flakes that are relatively cortical. Level 3 rotations are low, although this is perhaps a product of the small overall size of these flakes hence rotations are less visible on the smaller surface.

Platform characteristics are important determinants of flake morphology (Dibble 1997;Dibble and Pelcin 1995;Shott, et al. 2000) and can point to changing reduction strategies because platform attributes directly convey changes in knapping decisions in terms of point and angle of force. Platform characteristics show intriguing relationships with other flake characteristics, but the patterns are difficult to explore in the aggregate. As with multivariate analysis in cores above, the patterns discussed in flake morphology in the workshop test unit can be further explored using cluster analysis.

Cluster analysis on Complete Flakes

Cluster analysis of flakes from the Q02-2u3 pit elicits groupings from the numerical variables taken on complete flakes, and provides a way of reducing the dimensionality of the flake morphology dataset without the limitations of typological classification of flakes. Thirteen numerical measures were gathered on complete flakes and when these thirteen were included in the cluster analysis it was apparent that ten of the measures were related variables because they were measures that reflect overall flake size. As a consequence, the clustering solutions that emerged, regardless of the clustering method employed, tended to reflect the size groupings of smallest, medium, and largest measures in most attributes. A reduction of dimensionality was needed to collapse these correlated size measures into fewer variables so that a second order of variability in attributes that were not size dependent could emerge. Dimensionality can be reduced by conducting a Principal Components Analysis on the data prior to clustering, and then clustering the components with Eigenvalues of approximately 1 or higher.

Clustering the results of Principal Components Analysis (PCA) has precedence in archaeology going back to the 1970s (Ahler 1973;Redman 1973). In this study, the thirteen variables were first reduced to four PCA components and, subsequently, a Ward's Method clustering derived a 3 cluster solution from these 4 components. The numerical measures on complete flakes submitted to Principal Components Analysis include: weight, length, proximal width, medial width, distal width, proximal thickness, medial thickness, distal thickness, platform width, platform thickness, platform angle, percent cortex, and number of rotations. Mean values were substituted for empty values in the PCA. In this study, four PCA components with eigenvalues greater than 0.988 were clustered accounting for 75% of the variability in the dataset. Next, these four components were entered into a cluster analysis.

A variety of hierarchical clustering methods were explored and the most appropriate clustering solution appeared to be Ward's Method where three clusters were derived with a minimum of internal variance. In Ward's Method, cluster membership is assessed by calculating the total sum of squared deviations from the mean of the cluster. By maintaining the smallest possible values for the error sum of squares then intracluster variance is minimized and intercluster variance is maximized.

	Function
	1	2
Plat Thickness	.571*	.094
Plat Width	.546*	.079
Width Prox	.528*	.202
Plat Angle	-.493*	.252
Thick Prox	.411*	.297
% Cortex	.297	.705*
Weight (g)	.208	.452*
Thick Med	.324	.451*
Thick Dist	.153	.424*
Length	.164	.394*
Width Med	.305	.345*
Width Dist	.107	.309*
Rotations	.006	-.060*
* Largest absolute correlation between each variable and any discriminant function

Table 7-22. Canonical Discriminant Function Structure Matrix in order of size of correlation.

Figure 7-25. Canonical discriminant chart for complete flake clusters from Q02-2u3.

In Table 7-22, the contribution of each of the different measures taken on flakes to the two functions that emerge from cluster analysis are shown. Function 1 responds to platform characteristics, the morphology of the proximal parts of each flake, and flakes with tapering widths. Function 2 primarily responds to the variables that reflect the overall size, cortex, and rotations measures of each flake.

This clustering solution brings out the variability by excavation level among flakes in Q02-2u3 that were discussed above. Broadly speaking, the clusters discriminate large cortical flakes from small, non-cortical flakes, but a third group, differentiated primarily by its platform characteristics, also emerged from the analysis.

Characteristics of Three Flake Clusters from Q02-2-u3
	F1(n=265)	F2(n=668)	F3(n=130)
Size and Platform	Longest flake class, and slightly heavier than F3 class. Includes the greatest size variability.	Smallest flakeswith the smallest platforms and moderate platform angle.	Moderately large flakes with very large platformsand very acute platform angles. Tapering significantly proximal to the distal. Slight tendency for faceting as a form of platform preparation.
Cortex, Rotations, Terminations	Significantly more cortex than other clusters but only slightly fewer rotations. Many plunge terminations, few hinge.	Significantly little cortex. Few rotations. The most hinge terminations, fewest plunge.	Moderate amounts of cortex, slightly more rotated than other clusters.
Ob1 vs Ob2	Some Ob2. (n=14), 5.3%	Few Ob2. (n=20), 3.0%	Few Ob2.(n=5), 3.8%.
Comments	Largest flake class. These flakes are conceivably serving as blanks.	Smallest class of flakes and advanced reduction flakes.	Possibly corner removal flakes on tabular obsidian nodules.

Table 7-23. Q02-2-u3: characteristics of 3 clusters of flakes based on numerical attributes.

Figure 7-26. An example of a flake from the F1 cluster [L03-162.21].

Figure 7-27. An example of a flake from the F2 cluster [L03-162.118].

Figure 7-28. An example of a flake from the F3 cluster [L03-162.66].

These clusters capture much of the variability present in the flakes from Q02-2u3. Patterns among nominal attributes of these clusters are also worth examining. Non-numerical attributes could not be submitted to the PCA and clustering functions directly because only quantitative measures can be used with that procedure. Nominal attributes, such as flake termination, must be addressed using analyses measures of association such as Standard residuals and Cramer's V.

Flake Cluster		Termination
		Feather	Hinge	Plunge	Step
1	No.	166	20	62	13
	Std. Residual	-.3	-4.0*	5.0*	1.0
2	No.	431	154	59	22
	Std. Residual	-.2	3.0*	-2.8*	-.6
3	No.	93	18	14	5
	Std. Residual	.9	-1.2	-.6	.0

Table 7-24. Q02-2u3:c²showing types of terminations by flake cluster. On the whole, these relationships are not very strong (Cramer's V = .171).

In Table 7-24 standard residuals point to significant differences in the cluster 1 and 2 proportions of hinge and plunge terminations. In this table, a significant difference exists where ever the standard residual exceeds 1.96. However, on the whole, the table relationships are not very strong because the Cramer's V for the table is just 0.171. The proportions of hinge and plunge terminations are notably different between F1 and F2. The high number of plunges in F1 might be explained by these flakes serving as decortication flakes where plunging terminations can serve to clear off the bottom of the core to improve the chances of achieving feather terminations in subsequent blows. As a core maintenance strategy, plunging terminations can improve subsequent flaking events by increasing the striking angle. Furthermore, when the end of the core is non-cortical it increases the chance of feather terminations.

Other platform attributes of these flake clusters include an unusually high incidence of faceting on the platforms of F3 flakes. This kind of platform preparation is sometimes used to remove cortex or inconsistencies from the platform area. Furthermore, ac²table showed that Platform Angle, the distinctively low attribute of F3 flakes, is the variable with strongest association with the three cluster classification (Cramer's V = .457).

Interpretation with an Investigation of Flake clusters by Excavation Level

Investigating the proportions of these flake clusters by excavation level provides insight into the changing activities at the Maymeja workshop. A graph showing the proportions of these clusters by level will be shown and discussed in detail beginning with the oldest strata, the Terminal Archaic level 7 (2880-2650 BCE).

Figure 7-29. Graph showing Flake clusters by excavation level.

Level 7- Basal level

A high proportion of F1 flakes by weight was in keeping with expectations concerning early use of the workshop area. Early reduction of widely available large cores resulted in a large number of F1 flakes. The F3 flakes in this level had relatively acute platform angles.

Level 6- Large Platformed Flakes (F3)

An increase in F3 by count and weight in level 6 that persisted through later levels in the unit hints at a change in reduction strategy that produced these large platformed flakes. The defining characteristics of these flakes, are large platforms with very low dorsal platform angles, and these are very pronounced in this level within the F3 group. In reviewing the core clusters by level from Figure 7-22, there are few cores in this level and a relative prevalence of small cores, suggesting a decrease in availability of the large cores found in other levels. The production system that was dominant in level 7 had perhaps been altered by level 6 for lack of raw material in large nodules.

Level 5 -Core export level.

This level maintained roughly the same proportions of F1, F2, and F3 flakes, but the overall flake counts were much higher. In other words, a pattern that began in level 6 developed into full-fledged production strategy in level 5 because the proportions suggest that similar activities were being preformed but with higher production rates. The F2 flakes had significantly smaller platform thicknesses, a characteristic that fluctuated greatly between levels. The F2 flakes also had more rotations and they had much more cortex than F2 flakes did in higher, later levels. This suggests that smaller cores were being decorticated in level 5. Revisiting the core proportions from Figure 7-22, it is notable that large C3 cores dominated the assemblage of discarded cores in this level, despite the evidence from the flakes that small cores were in use. Hence, it appears that certain cores were decorticated and exported and therefore such cores appear in reduced frequency in this level.

A notable increase in the number of bifacially retouched flakes and broken bifaces is apparent in level 5, indicating that a pattern of some more advanced reduction activities was underway during these levels. There is also a slightly higher representation of Ob2 material among F3 flakes in this level.

Level 4 -Large flake blank production level

In general, production patterns first witnessed in level 5 continued at a higher rate in level 4. A¹⁴C sample from this level had a radiocarbon date from the Early/Middle Formative transition (1500-1320 BCE). The large F1 flakes had significantly more rotations while F2 flakes had fewer rotations. F2 flakes also had thicker platforms in this level, particularly contrasting with thin platforms on F2 flakes in the surrounding levels 3 and 5. All cores had significantly more rotations than in preceding and succeeding levels (see Figure 7-23), and this was particularly true of the tabular C2 core cluster. There was a slight increase in C2 cores in this level. These data indicate that further rotations were being applied, and that large tabular C2 cores, which were heavily decorticated and thus must have been extremely large to start with, were being discarded in abundance in this level. The level 4 excavation strata was also unusually thick (13.9 cm), therefore proportions are comparable to other levels while the actual count are not directly comparable. One significant difference between level 5 and level 4 is the presence of large cortical flakes in level 4, as shown in Figure 7-23.

Level 3 - Advanced reduction

Level 3 was distinguished because it contained a far greater number of small flakes and cores than did previous and subsequent levels. It was mentioned above that evidence of advanced reduction in level 3 included the discard of 13 broken bifaces yet only 2 retouched flakes were discarded. The many small flakes in this excavation level resulted in much higher artifact densities. Among the F1 flakes the lengths and weights were lower, while among F2 flakes the lengths were significantly longer, and among the F3 flakes weight dropped significantly. Thus, flakes in all 3 clusters shifted towards the smaller ends of their size categories. There were twice as many F2 flakes in level 3 than in previous levels, and they had low platform thickness, few rotations, and had significantly less cortex than did previous levels.

Cores in level 3 primarily consisted of large C3 cores that essentially replaced the C2 cores in this level. The lack of C2 cores suggests that the cores were either being further knapped, or they were being transported away through export during this occupation level.

The evidence from level 3 is consistent with workshop activities that had shifted from initial reduction to more advanced stages of reduction. The absence of large cortical flakes and large tabular C2 cores suggests that the investment in procurement that was supplying the cores to the workshop had changed,and perhaps excavating at the quarry q02-2 had ceased. As this is a workshop area with a long history of use, scavenging could have continued for many years as relatively large cores and flakes were surely extant in the workshop area. It appears that the system was essentially well-stocked in the beginning of level 3 but it appears that by the end of level 3 the easily available, knappable obsidian was relatively depleted.

Level 2 - Returning to production

Cores and flakes in level 2 return to a larger size scale. There were relatively few broken bifaces compared to retouched flakes. There are additional rotations on both F1 and F2 flakes, and F2 flakes had very little cortex and high platform thickness values. A return to quarrying at the q02-2 quarry is one possible explanation for the higher availability of material in these levels. In level 1, the F1 flakes are significantly rotated and some of the obsidian has notable quantities of irregular cortex.