Clovis Bevelled Bone Rods

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CLOVIS CULTURE BEVELED BONE RODS
By Jeb A. Taylor, G.I.R.S. Associate Editor

In Volume XLIII, Number 2, 2009, Prehistoric American, Michael J. O'Brien, Ph.D. and R. Lee Lyman, Ph.D. contributed one more in a long line of theories regarding the use of beveled bone rods by Clovis culture big game hunters.

We may never know for certain what these objects were used for. However, replication studies and common sense can help us to determine which are the least and most likely theories regarding their use.

As O'Brien and Lyman pointed out, the oldest theory is that, they are foreshafts. I believe this theory shows the most merit, so it will be addressed last. A second theory was posited by Wilke, Flenniken, and Ozburn in Clovis Technology at the Anzick Site, Montana. They argued that the rods were handle portions of composite pressure flaking tools used to remove flutes from Clovis points.

They demonstrated that a flute could be removed using this method. However their test was performed on opalite, a material that is extremely weak and easy to pressure flake. Even though the theory was tested successfully, it is unlikely that this was the intended use of these objects. Why would a Clovis knapper, for example, need 14 such specialized flaker handles, as were found at Wenatchee? Also, if they were part of a Clovis knapper's tool kit, why weren't other tools associated with knapping found with them: hammerstones, abraders, billets, etc.? And lastly, Clovis points are easily replicated using more conventional tools, so why go to all of the trouble of fashioning very labor-intensive bone flaker handles when there is no apparent advantage to them?

SLED SHOES

The next theory was offered by Dr. Richard Michael Gramly in The Richey Clovis Cache. There he claimed that beveled bone rods were used as "sled shoes."

Before continuing, I should mention that for a good portion of my life I lived in remote areas of Alaska and Minnesota. There I built my home and supported a family mostly from what the land offered. In the summer we traveled in birch bark canoes and in the winter we used sleds and toboggans, all of which I made from components split out of birch, ash, and cedar trees with relatively primitive tools, axes, draw knives, etc. And more importantly, paddled and pulled them many hundreds of miles through varieties of conditions, mostly, in hindsight, adverse!

Bone and/or ivory sled shoes were used in the Arctic by Eskimos, to protect precious wooden runners, and to create a wide smooth surface. However, their runners were flat in cross section to displace the weight of the sled, and were attached to the runners through counter-sunk holes.

If Clovis bone rods had been intended to be used as sled shoes, they would not have been trapezoidal , they would have been parallelograms. As they are, every other joint would snag on obstacles encountered.

Snow is very abrasive. If the bone rods recovered at Wenatchee (or anywhere else) had been used as sled shoes, their bottoms would have exhibited obvious flattening, polish, and striations. They don't.

And lastly, round is the worst possible cross section for sled shoes. They would have been extremely difficult to attach, and impossible to maintain.

Dr. Gramly provided a drawing of a sled equipped with these hypothetical sled shoes that looked very convincing. However, archaeologists appear to believe that if something can be drawn, it can be built and used, and that is not the case in real life.

(Dr. Gramly explained to me that, based on the position of the bone rods in situ, their being sled runners was the only logical conclusion that fit all the conditions of the Wenatchee site. - Editor)

LEVERED HAFTED WEDGES

This last statement is also true concerning the proposed hypothesis offered by O'Brien and Lyman that Clovis bone rods were used as "levered hafted wedges".

I must interrupt the flow of this discussion to explain that I have spent literally thousands of hours making and using stone tools, killing deer with stone tipped arrows, butchering them with stone knives, processing their hides with bone fleshers and stone scrapers, and making clothing with the tanned hides with bone awls and sinew. There may be others out there with more experience making, hafting, and using stone tools. If so, I am not aware of them. In any event, in this discussion, I am speaking from experience, not from hypothesis.

In positing their hypothesis, O'Brien and Lyman made a number of assumptions that if not outright incorrect, are certainly open to doubt. Initially, they made the assumption that the Wenatchee Clovis points were butchering tools because they were larger than most Clovis points recovered from Clovis kill sites. Their observations regarding their size was certainly correct, but their assumption regarding their use, although not necessarily incorrect, was at least presumptuous.

They then described the procedures required for hafting such large points/blades, stating that it took them almost two hours to apply 20 strips of sinew, waiting for them to dry, and then applying tree resin as a sealer. Judging frommy experience, sinew should never such as knife blades or scraper bits. Nor would any lashing, especially sinew, be covered with tree resin. Sinew is universally sized with hide glue, not pitch. Pitch is useful to seat points/blades into in their hafts, but not to apply to the surface of the lashing.
Blades the size of those from Wenatchee can easily be hafted in less than one minute with a stretched length of tanned hide or fiber cordage (hide is better). When the haft loosens, which it invariably does, it simply needs to be unlashed and re-lashed tighter. This can also be accomplished in less than a minute because, unlike sinew, tanned hide does not need to be masticated to reapply it and it is not covered with sticky pitch.

As regards the physics of their concept, I think it is impractical. Unfortunately, as was the case with Gramly and the sled shoe theory, their levered hafting wedge theory was also only illustrated with hypothetical drawings, as opposed to actual images or scale drawings of actual models. In any event, the drawings are of a hafted lanceolate point rather than a broad based point/blade like those from Wenatchee, so I assume that no actual models were ever made or tested. If they were, a stronger argument could be made in their defense.

FORESHAFTS

In regard to the 1936-37 excavation at Blackwater Draw #1, Marie Wormington states in Ancient Man in North America:

In addition to the stone artifacts, two extremely important. Polished bone pieces were found in situ. One was lying near the foreleg of one of the mammoths; the second near the tusk of another. These are tapering cylindrical bone shafts with a beveled end.

The fact that two beveled bone rods and two projectile points were found with mammoth remains is not proof that beveled bone rods were used as foreshafts. However, I would think that is does fall into the category of evidence, and it is clearly worthy of further consideration.


POSSIBLE CLOVIS HAFTING STRATEGIES
(TAYLOR, 2006)

THE "V" NOTCH HAFTING STRATEGY
Clovis projectile points exhibit a high degree of variability and size for a single projectile point type. This was undoubtedly due to a combination of temporal and spatial considerations: the range in size of their intended prey, accessibility to raw materials, attrition, or personal preferences. On the High Plains, Clovis points were generally fluted or basally thinned for a distance of 15mm - 25mm. Thinning was accomplished by single strikes, multiple strikes, pressure thinning, or any combination of these. Interestingly, even though Clovis points exhibit considerable morphological variability, they exhibit a surprising amount of conformity through their hafting areas.
The hafting area on Clovis points begins with a relatively sharp basal margin, and as a result of fluting and/or basal thinning, a wedge shaped hafting area is created that expands up the stem at a rate of about 12° - 16° (Figure 2). Uniform hafting areas on projectile points are desirable because they are easier to replace, but possibly of even greater importance to mammoth hunters may have been that foreshafts with corresponding "V" shaped notches were considerably stronger than foreshafts with mortised notches.

A "V" notch is hypothetically stronger than a mortise notch because less mass is removed from the critical notch termination area. Experiments performed by the author to test this hypothesis, though, were inconsistent due to variations in shaft diameters and the inherent strengths of different species of wood. However, the results suggested that foreshafts with "V" shaped notches required 18% to 44% greater sideways force applied to them to initiate shaft failures.


Figure 3. The split "V" shaped notch hafting strategy 3A: Illustration showing how a "V" notch is created in a split shaft.

3B and 3C: Profile and face views a point hafted in a split "V" notch. The point is a cast of one of the original Clovis points from the Dent Mammoth Kill site, and the foreshaft is chokecherry.

Interestingly, the surface between the point and shaft mated perfectly without any trimming or fitting. Only the outside of the shaft was trimmed so that it tapered nicely into the surface of the point (Figure 3B)

Replication studies have shown that lashing on spears and darts is best accomplished in two stages. The shaft reinforcing lashing (Figure 3B) is separate and does not need to be removed when replacing points, but the haft lashing (Figure 3C) usually has to be cut off and is consequently destroyed.

This type of notch can be created very simply by splitting the shaft and inserting a projectile point into it. With this approach, no mass is removed from the inside of the notch; instead, it is trimmed off outside to create a smooth taper into the face of the projectile point (Figure 3A and 3B).

COMPOSITE FORESHAFTS WITH "V" NOTCHES

Another method for creating a "V" notch appears to have been used by Clovis craftsmen on bone. Bone cannot be split and bent the way wood can, so bone shafts were created using a composite method. This required that the end of the shaft be cut at an angle that corresponded to one half the angle of a Clovis point's hafting area (6°- 8°), and that a corresponding beveled piece be lashed to it to make up the other half of the "V" (Figure 4A).


Figure 4. Composite "V" shaped notch Clovis hafting strategy.

4A: Components of a composite "V" shaped notch haft
4B: Profile view of a beveled bone rod, Blackwater Draw, New Mexico (cast)
4C: Rotated view of Figure 4B (notice distal portion is missing)
4D and 4E: Two views of a chokecherry reconstruction of the beveled bone rod shown in Figures 4B and 4C with a cast of one of the original Clovis points recovered from the same site.


CLOVIS BEVELED BONE RODS

What is known about beveled bone rods is that they are generally:

- made from mammoth bone or ivory
- 150mm to 250mm long
- wider than they are thick
- 10mm — 30mm in width
- 10mm — 22mm in thickness
- beveled on at least one end (some are unibeveled and some are bi-beveled)
- scored on the beveled surfaces with cross hatching
- found with Clovis points and bifaces in caches and in kill sites

Most Clovis beveled bone rods exhibit some degree of disintegration and are therefore difficult to measure accurately (Figure 4B and 4C). However, after studying a number of originals, casts, and illustrations, it appears that the angles of the bevels on many of them are about 6°- 8° off their vertical axes. Therefore, they would mate quite well with the hafting areas on most Clovis projectile points (Figures 4D and 4E).

Initially, bi-beveled bone rods were thought to be foreshafts, and bone rods with bevels on one end and points on the other end were thought to be projectile points. This is of course a possibility, although personal experience in hunting mammals with pointed arrow shafts has led me to the conclusion that arrows without points that cut are almost worthless. It is more likely that both types of bone rods were foreshafts, and that bi-beveled varieties were attached to their main shafts with the overlapping splice method (Figure 5A) and the pointed varieties were attached to their main shafts by the socket splice method (Figure 5B).


Fig. 5

In light of the fact that beveled bone rods are typically found associated with Clovis points in caches and kill sites, and that, as demonstrated above, they work admirably well as foreshafts, it seems quite plausible that this was their intended use.


Duplicated from the “Resources” section of arrowheads.com and reproduced with permission.

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A FURTHER NOTE ON THE EAST WENATCHEE CLOVIS SITE
By Michael J. O'Brien, Ph.D. and R. Lee Lyman, Ph.D.

In Dr. Leslie Pfeiffer's excellent article on the East Wenatchee Clovis site (also known as Richie–Roberts) in central Washington, he states that among the most important finds at the site were 13 beveled bone rods made from mammoth or mastodon limb bones.

(Pfeiffer 2008). (There actually were 14 rods, one of which was extremely fragmented.)


He points out that "While there is no doubt that the Clovis people used mammoth bone in many ways, including bone points, the best hypothesis is that these bone rods were likely foreshafts to mount stone points to wood shafts" (Pfeiffer 2008:76).

This is a widely held proposition in American archaeology, going back to at least the work of Luther Cressman (1942) in the Great Basin and that of John Cotter (1954), one of the original excavators of Blackwater Draw, the Clovis type site. The proposition later received formal expression from Larry Lahren and Rob Bonnichsen (1974) based on their analysis of the Anzick Clovis "burial-cache" materials from Montana (Fig. 1) and even later from Dennis Stanford (1996), who proposed a compound arrangement of beveled rods to create a hunting shaft. After considerable analysis of bone and ivory rods from across the western United States, coupled with engineering-design analysis of the rods from East Wenatchee (Lyman and O'Brien 2000; Lyman et al. 1998), we offer a different proposition - that many of the rods served as levered hafting wedges.

Most of the functions posited for bone and ivory rods - foreshafts, points, sled shoes, and so forth - have been based on suspected analogous specimens, especially those from the ethnographic and late prehistoric records. The problem with such an approach to explaining the archaeological record lies in the requisite assumption that the past is no different from the present - that the uniquely historical development of technology is denied as we force our archaeological observations into some ethnographically documented category of phenomena. Usually what happens is, the more we start investigating details of construction, the more the arguments start to fall apart. Thus, we began our research without reference to ethnographically documented uses of rods and merely attempted to build a tool that functioned efficiently and simultaneously accounted for numerous features evident in the archaeological record. In short, we employed mechanical inference based on experimental evidence.


Figure 1. Lahren and Bonnichsen (1974) models of beveled bone rods functioning as foreshafts: (left) single-beveled specimen, shaft, and projectile point; (right) bi-beveled specimen, shaft, and projectile point.

One thing that struck us as we compiled data on Clovis points from well-known caches in the western United States was their large size compared to that of points found in association with mammoths or bison at sites such as Black Water Draw Locality No. 1 (New Mexico), Lehner and Naco (Arizona), Lubbock Lake (Texas), and Sheaman (Wyoming) (Fig. 2). In fact, six of the 14 Clovis points from East Wenatchee originally reported by Michael Gramly (1991, 1993, 1996) were larger than any of the other 64 cache or non-cache points in our survey (Lyman et al. 1998). The exceedingly large size of the Clovis points from East Wenatchee suggests they were intended to be used as butchering tools - specifically, saws - rather than as weapons designed to pierce hide. Gramly (1991, 1993), in fact, refers to them as "knives."

Other attributes of these particular specimens appear to validate such a categorization. For example, they all have either parallel or slightly convex blade edges, rather sinuous edges, and nearly straight to noticeably concave bases, the latter forming either a shallow V or a (sometimes deep) U. We suspect all these features are functionally and mechanically related. The specimens with convex edges could have been resharpened more times than a parallel-sided or distally converging-sided specimen. Further, specimens with convex edges, if used as weapons, would have cut holes through hide that would have been larger than holes made by points with parallel or distally converging blade edges, the former allowing penetration of a foreshaft or shaft.

We believe the association of rods with Clovis points in settings where animals were butchered - such as at Blackwater Draw - and in caches - such as at East Wenatchee - is not simply fortuitous. The fact that 14 fluted projectile points and evidence of 14 bone rods were found in the East Wenatchee cache suggests that a ratio of 1:1 of these two kinds of implements might be significant. Given these considerations, our experimental goal was to build a butchering tool - not a projectile - that employed both the large stone points and the rods. Using the specimens from East Wenatchee, as a model, we focused on two things: building an efficient butchering tool - one that required minimal maintenance effort during use - and determining the function of the rods.

One critical issue in manufacturing an efficient butchering tool is how the blade is hafted to the handle. Our experimental work indicates that the amount of sinew required to haft a biface depends on both the size of the shaft to which the biface is hafted and the size of the biface. A 6- to 8-cm-long Clovis point that is to be used as a projectile point can be hafted with a single strip of sinew 0.5 cm wide and 30-40 cm long. Seating the point, wrapping the sinew, and allowing the sinew to dry sufficiently to tighten takes about 30 minutes if the air is dry and warm, plus additional time to apply mastic. Hafting larger bifaces - such as those from East Wenatchee - that are to be used as saws requires as many as 20 strips of sinew 0.5 cm wide and 40 cm long. The greater amount of binding is required because the handle has a larger diameter than a dart shaft, and the force applied to the biface during use as a butchering saw is different than that applied to one used as a projectile point. Because more sinew is required, and the haft comprises multiple layers of sinew, the entire process of seating the biface, wrapping, drying, and applying mastic to the haft has, in our experiments, taken almost two hours.

If the sinew binding absorbs moisture (which it does quickly if it is completely dry prior to use of the tool), such as from body fluids of an animal being butchered, the binding expands and becomes loose. Coating the sinew with mastic (e.g., tree resin) tends to waterproof it and extend the use-life of the haft, but a haft will nonetheless loosen through use and moisture absorption, even if coated with resin, which will wear off or flake off if it becomes hard and dry. Because it takes a rather long time to rehaft (particularly) large bifaces - the resin must be removed, the sinew unwound, the point reseated, the sinew rewrapped and allowed to dry, resin applied - the mechanical problem is to prolong the use life of the initial hafting. This can be accomplished by tightening the sinew via a wedge inserted between the sinew and the shaft to which the biface is hafted. Engineering evidence indicates that the beveled rods from East Wenatchee served this binding-tightening wedge function.

In the barest of terms (see Lyman et al. [1998] for details), here is how the wedge works vis-à-vis the complete composite tool. During manufacture of the handle that eventually will hold the stone tool, a groove is cut in the wooden shaft or handle and extended onto the (tapered) nock tang (Fig. 3). This groove, used for seating the rod, should be at least as long and wide as the rod and about half to two thirds as deep as the rod is thick. Sinew is bound onto the shaft or handle as tightly as possible prior to inserting the rod. Before the sinew completely dries, the rod is set in the groove cut for it and is shoved up under the binding (Fig. 4). After the sinew has dried, the rod is levered down into the groove and the proximal end held in place with leather or sinew binding. The fulcrum should be distal to the center point of the rod length. The levering down serves as the final tightening of the sinew. It is this final levering down into the groove that mechanically explains why the face opposite the bevel must be convex rather than straight; were it not, the rod would lie flat in the groove and no lever-enhanced tightening of the sinew would be possible.

Grooves, usually in the form of crosshatching, cut into the bevels of the rod help keep the sinew and rod from slipping during use. As the sinew binding dries, it shrinks and sets down into the grooves cut in the bevel of the rod, making a mechanically sound haft (Fig. 2). (The photograph made by Pete Bostrum of the longest bone rod from East Wenatchee [Fig. 5], is an excellent close-up of the crosshatching found on the beveled portions of many Clovis rods.) Without crosshatching on the bevel, the rod has a tendency to slip out from under the sinew binding when it is levered down. The fewer, generally less deep grooves sometimes evident on the convex face opposite the bevel help secure the rod to the fulcrum area (Fig. 4) of the groove in the handle when a bit of hide is used to raise the fulcrum.

The hafting-wedge function of the rods readily accounts for why they were beveled on both ends. Should the beveled end being used as a binding wedge fracture, one has but to merely turn the rod around 180 degrees, insert the intact edge under the haft binding, and lever the rod down to maintain a tight binding. Beveling of the proximal end-toward the handle-also allows the binding holding it down to be more easily slipped on and off the levered-down end of the rod. The basically cylindrical cross section of the rods can be accounted for by noting that we have found it to be relatively easy to carve a groove for the rod that is curved in cross section using a scraper with a convex bit. Finally, the thick cross section of the East Wenatchee rods would have made for a larger cross section under the bevel, where the most force was concentrated when the rod was being used to tighten the haft binding.



In summary, we believe we discovered a way to haft large fluted Clovis bifaces that produces a mechanically efficient tool, which we have used to butcher large game and cut frozen meat easily. It would be a very efficient tool to use if faced with a proboscidian carcass. Our engineering work takes into consideration a suite of attributes of both the fluted stone points-sinuous convex edges, flutes, large size, concave base-and the bone rods-bevels, scoring of bevels, convex face opposite the bevel-in the East Wenatchee cache. These sets of attributes are functionally and mechanically interrelated in the final tool, which we believe accounts for (1) the co-occurrence of the large points and the rods in caches and in butchering contexts, (2) the breakage and wear evident on some rods, and (3) the varied sizes of both points and rods.

As a final note, we point out that the idea for our work came from Virgil Hayes, who also carried out all the replicative work. He joined us as co-author on the original paper, which was published in Journal of Archaeological Science (Lyman et al. 1998). Hayes never had any formal training in archaeology, but he possesses keen insights into ancient technology and an innate ability to reverse engineer what he sees. His experimental work is yet another excellent example of the significant breakthroughs and discoveries routinely made by nonprofessional archaeologists.


Duplicated from the “Resources” section of arrowheads.com and reproduced with permission.