25
UNIFACIAL COBBLE-TOOLS FROM THE NORTHWEST CALIFORNIA COAST:
EXPERIMENTAL AND WEAR PATTERN NOTES
Thomas R. Hester, Elizabeth Wuertele, and Robert F. Heizer
27
Archaeological sites along the northwest coast of California in the territory
occupied at the opening of the historic period ,by the Yurok tribe have produced an
iteresting series of unifacially chipped basalt cobbles. These artifacts are known from
both excavated and surface contexts in Humboldt County (Fig. 1). The specimens
described here are from the following sites: CA-Hum-169; CA-Hum-120; CA-Hum-118;
CA-Hum-125; and CA-Hum-129.
Site CA-Hum-169 is the historic Yurok site of Tsurai in Trinidad Bay
(Waterman 1920: Map 34, p. 271; Heizer and Mills 1952; Elsasser and Heizer 1966).
Site CA-Hum-120 is the historic Yurok village of Tsotkskwi (Waterman 1029: 265)
where in 1948 a single test pit was excavated. Site CA-Hum-118 is now within the con-
fines of Patrick's Point State Park. It was a hunting camp occupied into the historic
period. It was excavated by the University of CalifoDrnia Archaeological Survey in
1949 (Elsasser and Heizer 1966). Site CA-Hum-126 isthehistoric Yurok site of Keken
(Waterman 1920: 266). It was pothunted by a Eureka relic collector whose other activity
was dentistry. In the summer of 1948 a University of California Archaeological Survey
party dug two test pits here. Site CA-Hum-125 is the historic village of Maats
(Waterman 1920: 266). The specimens recovered there came from the surface during
a brief visit in 1948. Site CA-Hum-129 is the historic Yurok village of Tsapekw. At the
time of a 1948 visit, there was a single occupant, an old Yurok named John Kirk who
was born at Gold Bluff and who was apparently living there in order to protect the
graveyard from depredation. He was willing to allow the excavation of two small test
pits, and from these the specimens described here were recorded.
Other materials found at the above listed sites all fall in the range of known
Yurok material culture items. All the sites were presumably permanently occupied.
For the way of life of the coastal Yurok see Waterman (1920); Kroeber (1925).
Neither of these refer to the unifacial cobble choppers such as described here, perhaps
because they were so commonplace that more exotic items were more interesting.
THE ARTIFACTS
Forty-seven specimens were selected for study (see Table 1). All are in the
collections of the Lowie Museum of Anthropology, University of California, Berkeley.
In general, the artifacts are made on ovoid to elongate-oval cobbles of basalt (presumably
secured from beaches in the area). On each, a unifacially chipped edge has been formed
at one end by a series of percussion blows. The flaked ends of the cobbles exhibit
working edges which range from oblique (Fig. 2, c), to straight or slightly convex
(Fig. 4, b), to markedly convex (Fig. 3, b), or pointed (Fig. 7, b). The extent of
flaking that went into the formation of the edge is also variable; in some instances (cf.
Fig. 4, a), only a few flakes were detached. In other cases (cf. Fig. 3, a), specimens
have been flaked over as much as half of one face.
28
We have illustrated 17 specimens in detailed line drawings prepared by
Judith Ogden (Figs. 2-7); the only previous illustrations of which we are aware appear
in Elsasser and Heizer (1966: P1. 16, c-f). These will serve to provide additional
descriptive detail. Table 1 summarizes the dimensions and weights of the specimens,
and also provides data on site provenience, catalog number, and individual wear
patterns. Edge angle data as measured with a goniometer are also found in Table 1.
Specimens with morphological and technological attributes similar to these
California examples have been found in many parts of North America. In some regions,
such as Alabama and the Southeast, somewhat smaller specimens are attributed to a
"pebble tool industry" which some archaeologists believe to be of great antiquity. A
recent reevaluation of these "pebble tools" is provided by Dragoo (1976: 7). In the
Fraser Canyon of British Columbia, Borden (1968) found similar artifacts at sites
thought to be of late Pleistocene age. He describes these Canadian specimens (illustrated
in Borden 1968: Figs. 4-5) as "pebble tools" or "core tools made on well rounded
river cobbles."  Borden suggests a wide variety of functions for the implements, but
notes that no wear pattern studies had been done, at that time, of his sample. Many of
his specimens are closely similar in size and technique of manufacture to the Humboldt
County arfifacts.
AGE OF THE SPECIMENS
Three radiocarbon age determinations from Humboldt County sites are rele-
vant. Charcoal from just above the clay subsoil at site Hum-118 (Patrick's Point)
gave an age of 640 + 90 years B. P. (1310 A. D. Elsasser and Heizer 1966). One
age determination for Hum-67 peat which lies at the base of the Gunther Island site
(Hum-67) gave an age of 900 A. D. (Heizer and Elsasser 1964: 35). This is sample
M-938 (1050 + 200 years B. P. ).
Most of the examples of unifacial cobble tools described here come from the
surface of sites. A few from sites Hum-118 and Hum-67 show these to have been used
sometime in the period of 1300 and 1400 A. D. and the abandonment of the site in the
late nineteenth or early twentieth century. Cobble tools from the other sites are all
named villages occupied into the twentieth century. So, these tools are recent, but we
do not know how early they were used.
EXPERIMENTAL AND WEAR PATTERN DATA
In 1973, one of the authors (Wuertele) was a student in a seminar on experi-
mental archaeology taught by Hester. Her research centered on the use of stone tools
of various kinds which were presumably used in a variety of wood-working activities
(Wuertele 1973). As a part of her experiments, Wuertele utilized two unifacially
chipped basalt implements from Hum-67. These were both surface specimens and
were resharpened and used for experimental purposes. The specimens were used on
29
redwood (Sequoia), the most common wood in the northwest coastal area. They were
omployed by her in scraping, adzing, and chopping tasks. One specimen (tool #16 of
Wuertele 1973) was used for a total time of 110 minutes, the other (tool #17 of Wuertele
1973) for 70 minutes. Tool #16 had an edge angle of 650, and tool #17 had one of 55
The use of tool #16 on redwood as a multipurpose tool for scraping, adzing, and chopping
activities produced wear patterns on the edge in the form of nibbling and dulling. Tool
#17, used solely for the chopping of redwood, resulted in dulling wear along the edge.
We wish to point out that these experiments were part of a much larger project, and we
have extracted these data simply because they are the only experimental results which we
have available at this time.
Also in 1973, Hester and Wuertele conducted a wear pattern and edge angle
analysis of 47 of the unifacially-chipped cobbles. Wear pattern studies were done with
the aid of a binocular microscope, with magnification powers up to 70X. During the
recording of the wear pattern data, descriptive notations were made and measurements
and weights for all specimens were recorded. This information is found in Table 1.
We provide this detailed listing since we are unable to find any other published descrip-
tions of this tool form in the California literature.
As Table 1 indicates, the primary wear pattern repeatedly observed on the
archaeological Humboldt County tools was dulling. This was often accompanied by
abrasion (varying from highly localized areas of fine scratches to a near-polish)
adjacent to the working edge but sometimes extending onto the dorsal (or occasionally,
the ventral) flake scars. The striations, or major scratches, noted on the implements
generally ran perpendicular to the working edge. Nibbling (step-fracturing) is also a
recurrent wear pattern seen on the tools. An examination of the pertinent literature
reveals little comparative data on the experimental use or wear pattern analysis of
similar tools, exceptions being reports by Crabtree and Davis (1968: 428) and
Phillipson and Phillipson (1970). The limited experiments of Wuertele (1973) suggest
to us that the tools could function as choppers or, at times, in a combination of chopping-
scraping-adzing tasks during the wood-working process. The dulled and step-fractured
edges, along with ventral and dorsal abrasions of the flake scars along the working
edge, suggest repeated imbedding of the tool edge into a material like wood (cf.
Crabtree and David 1968: 428). The ventral striations on the tool may reflect the use
of the implement in preliminary shaping or roughing-out of wood, perhaps in an adz-
like fashion..
A review of the edge angle data (Table 1) reveals a clustering (34%) of edge
angle values in the 550-640 range, although a substantial percentage of the tools (57. 9%)
have edge angle values that are fairly evenly distributed if one examines 100 increments
between 560-840. The mean edge angle for the series of 47 specimens is 68. 480.
We have no evidence to indicate whether or not the Humboldt County tools
were hand-held or were hafted, although we suspect it was the former. As noted above,
the experimentally-used specimens were hand-held during the course of Wuertele's
experiments.
30
During the life of the tool, there is ample evidence of a continuing process of
rejuvenation or resharpening of the working edge. Once an edge became dulled, or had
been step-fractured to the extent that it was no longer serviceable, the edge was re-
sharpened (Crabtree and Davis 1968). This process involved the removal of flakes
from the dorsal face of the edge, struck from the ventral surface (see Fig. 8, a).
Occasionally, flakes were detached from the ventral face by blows struck perpendicular
to the edge, similar to the "Retouch Method C" described by Shafer (1970: Fig. 2, e;
compare with Fig. 8, b). A newly resharpened edge is sinuous and has pointed protru-
sions (e.g., Fig. 6, d). The tools were obviously valued and underwent a series of
resharpening episodes, each sequence leading, of course, to a reduction in size.
Specimens like those shown in Fig. 2 may represent nearly-exhausted implements, due
to repeated resharpening.
ETHNOGRAPHIC COMPARISONS
One interesting ethnographic observation regarding the use of similar cobble
tools is provided by Mitchell (1958: 192). Among the Australian aboriginal groups on
the New South Wales coast, the mainland of South Australia, and several other
Australian localities, Mitchell notes the occurrence of "crude chopping and cleaving
tools.   and describes them as follows:
"These comprise pebble choppers, either unifacial or bifacial types,
used as hand axes and not made to be finished off by grinding. They
are made from flattish pebbles of varying sizes by carefully flaking
on one end, or on one or both lateral margins to obtain acute-angled
working edges, . .. " (Mitchell 1958: 192).
The following functional observations on these pebble choppers is also provided by
Mitchell:
"Utilizing a pebble chopper, a sapling eleven Inches in circumference
was cutdown in four minutes".
Tindale (1941) has also recorded the use of crude hand axed by the natives
of Western Australia. These tools, made by flaking an edge on a large flat boulder
were used for cutting down trees. Tindale notes that a sapling six inches in diameter
could be cut down in two minutes. The tools were retrimmed as they became dull
through continued use.
SUMMARY
In this paper we have described a distinctive series of unifacially flaked
basalt artifacts from the northwest coast of California. Although numbers of these
31
tools have been collected from sites in the region (particularly in Humboldt County),
they have not previously been the subject of detailed description.
A sample of 47 specimens from the collections of the Lowie Museum of
Anthropology was scrutinized for wear pattern evidence. Characteristic use-wear
included dulling of the working edge, nibbling or step-fracturing resulting from use,
and abrasions of flake surfaces caused by repeated contact with the material(s) being
worked. Edge angle measurements suggest that a steep working edge was preferred
by the aboriginal tool-user. This observation is borne out by evidence of repeated
resharpening of the working edge during the life of the tool. As a part of the overall
study of these artifacts, brief experiments were conducted. While these were too
limited in scope to be conclusive, the use-wear found on the tools after thfe experimental
working of redwood were found to be quite similar to that occurring on the archaeological
specimens.
We cannot, with such preliminary data, offer any substantive interpretations
as to the function of this tool form. However, the combined analytical and experimental
data, when supplemented by published studies, such as that of Crabtree and Davis (1968),
lead us to suggest that these implements were used as choppers or some functionally-
related task (such as occasional scraping or adzing) in the wood-working process. We
do not know whether they were used in certain specific acitvities or whether they might
have indeed seen use as multi-purpose implements. The uniformity of the wear pattern
data would seem to be indicative of the former. We can only hope that the publication
of the descriptions and wear pattern data in this paper will spur others to carry out
more sophisticated experimental studies involving this tool form. Certainly a more
careful examination of the context of these tools in future archaeological investigations
in the northwest coastal area will aid in a more meaningful functional interpretation.
O
0   U
Ca~~~~~~$
.2     bi C- 4 -4 C40
Oc     e S OO 0
0_    q:  0
e   co   4- or- 0   ; E 4
cd 0cCo
Q bI3      0
Gs 4 _  ; t >  r  fi
o   0 0 0 0 0 0 0
_*o 0 0  co 0 0 0 0
00O**00*
LLOC000o00 00l 00 t
* * * * * 0     00
8 Cs O ci Cs CY,, o
w Xo O   CY oo C
0
0;
00
C0
0
00
'-4
cq
Cl
Lr)
'-4
CL
Uq
00
Cl
00
cs
lc:v
cq
Cl
00
0
00
'-4
U
C0
.1-1
.+i
C.0
'-4
1-4
'I
0    0  0  0  0   0  0  0  0  0   0  0  0   0  0  0  0   0  0
o   o CO CY              0 L  L  o L  00 o  o  O t  00 o C9 O  O
oo cs0 ld co  o c- ul eo C.0 LO CC0 o.o   U: m CD 00 C-    c
r- r- O) r- O) r- r- LO cq o LO qd LO t- Cf to T       dq LO
o; C4 C4 C4 : O     dq t  C4 C4  t; 4  Lf e  C4 CO C4 4   4
cs ts tD    tD Le     c; a;       c o   oo
0  0  0     0   0       0   0
00
.
'-
0 CL
*~ A
co e
L       0     0   CD      0
*.    *8 *8 *f        C
0 t0  0  0  0  0  0  0  CD  0  0-  0 O 0  0 0  D  00  0
Cq r- t-
.
00
00
er-
1-I
'-I
00
UD
00 cq
0
00
0
cq
Cl
to.
cq
Cl
0-
0
00
00
qli
cq
0
C
C.
0;
LO
Cl
CDC CD CD
ci C i cq   cq
00
C.0
C.0
00
0
cq
l
0-
0
00
00
0
Cl
to.
IO
cq
Cl
U-
Cl
cq
Cl
0
0
.
LO
0
00
00
r-
.
00
c0
0
a:
Is
r-q
0
Cl4
'-4
?D
'-I4
0
'-4
cq
"It
C)
m
0
cq
Cli
U
* t4
0to
Lo LO
00
cq
Cl
K:-
'-4
cq
Cl
00
00
0
0
'I
cs4
cq
.4
cs
oo
00
m
00
'-4
'-4
?
00
.
LO
1-4
00
00
%l
C00
00
CO
1-4
C0
U
t.
00
00
C00
0
CO
i
V-
CD
CU
'-I
LO
CD
i-1q
01
CO
5
0
LO
to.
00
00
00
m
0
CD
1-4
U
.-
00
Cl
-It
0-
0
CO
?
1-4
K:-
00
Cl
K:-
CO
Cl
'-4
UI
0
00
00
.
00
0:
C0
CD
U
0
00
00
I
C0
0
0
CO
Cl
'-4
Ca
Ca
4-  0  c
0~ 0
a)-
. C.O.
a0
Cn
0
o
"-I
9             4
C Q
o w
'I:          c m
0 >^      4
4-J C *
a)
btb
"o
a)
0
0
8:
0
Ca
a 1)  Cd
k.A   c
a)
f4-4
0
~0
.8~ -4
9"4
4 ?
Fjm
C
*h
0  *O4
m ?;
C4o
oq =
u o
5 a
U o
E- Y
-C4
Qeit
o,~-
o
*4
m-  ~
?
O.
0  0
0
U5
'-4
00
'-4
cq
tr
COi
Cl
U
0
Co
0
Co
C.  aC
WD .
*o Q
CPC4
4 .  Co > )
iCo a)Q
Cd bD
0 4 a)
.P2  ss  n
m  4-
S.4.  C) ~
a)  4-0
P 0"0*"
0^E
IE; CD2
,d  bi w
0 0       to 0 o
to o 100
oo CD LO   LO
LO t- L LO CO
*  *  S  *  S
Cs O Co
0
Co
s0
a)
-
"0
Co
S:L O
Q
o -
a L)  0
O   _
0 Ce  S
0
~Co
0
Cd"
cCd
a)a
0
oi
Qd
$4
?
Cd
tg
0
O4)
*-6^
Co
Cd
Cd
C)
O_4
"0
P _
av
a)a()
.-I S.
a)a
CI3
4.)
a)-
4p0~
~Co
Cd
0
Co
0
._4
Cd
p0
ICea
_ M
Cd *^?
ea)
C3.fIV
pop ~..
00    00 0     0    00 0 0
00L    0 o     t-   00 00 Cq O
CD CD  tCoC    Co   00 C0  C
c~C;                          Co4  L
00 H t
Co  4 t-
Om
Cd
C,  Cd
a)  C  a)  a2=
o~~~~~~~~~~~~~~~~~~~~o-
;4 4j rg z
0    00 0 0
0    L O  LO
0    C L F b
Co
.
t-CY3      q       -4
;       04    *      S
*-   0   to   5f      5
i-I
100  O C>  r1L- c
CD t4  00  o;0  00
0        0     0 0 C0
0
0
Co
CY)
04
0C
'-4
0
CD
'-I
I
0
to
CD
00
'-I
00
CLf
Co
00
Co
00
00
0
r 0000o LO
0      0  *  *  *
00 c 0 cDc
00 I-
0y-;
CoV--
Co
00
00
1-I
0
'I
CQZ
co
C%
r-l
0
ul:
to
00
00
0
cq 0
m     t
CD
t-
'-4
CD0CDCD 0CD     i-4     CD0
~I                   I
rq r4 r- r-      r-      -
33
P-4
01
. ?
0
00
00
.0
00
Co
a)
Q)
a)
Cd
a)
a)
NO
0
a-)
4-)
*I
a)
Co
4)
4-b1
-p4
a)
Co
a)
a)
4.)
a)
* S b~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~C
a)
00
0
OC
LO   b et-O
* *; *; t
o O-
co
C.
00 00
*  0
00
000
CD CD
C 00 0 00
00
to
00
CD
CD
C.0
0
CD
4.)
ba
o .
0
tO
0
00
Lo
m
00
Co
0
0
t:-
to
Co
C0
T-l
CD
cq
LO
.
to
0
0
CD
00
Co
0
0
00
.
to
00
'I
0
8
CD
00
0
0
'-I
to
CD
L0
L-I
a
00
C.0
00
mt
.
.~
p
CD
00
Co
0
CD
CD
CD
00
0
I
'-4
0
cq
0
0
'-4
CD
00
CoD
0
0
CD
Col
cO
CD
ri
m
CD
CQ
CD
C1I
rI
y
Co
Co
00
0
I I
z
C0
00
Co'
0
0
C0
CI
Q0
cq
CD
Czj
Cq
CS)
34
BIBLIOGRAPHY
Borden, C. E.
1968
Crabtree, D. E.
1968
Dragoo, D. W.
1976
A Late Pleistocene Pebble Tool Industry of Southwestern British
Columbia. In: Early Man in Western North America (C. Irwin-
Williams, ed.). Eastern New Mexico University, Contributions in
Anthropology 1(4): 55-69.
and E. L. Davis
Experimental Manufacture of Wooden Implements with Tools of
Flaked Stone. Science 159 (3813): 426-428.
Some Aspects of Eastern North Airmerican Prehistory: A Review 1975.
American Antiquity 41(1): 3-27.
Elsasser, A. and R. F. Heizer
1966   Excavation of Two Northwestern California Coastal Sites. University
of California Archaeological Survey No. 67: 1-149. Berkeley.
Heizer, R. F. and A. B. Elsasser
1964  Archaeology of Site Hum-67, the Gunther Island Site in Humboldt Bay,
California. University of California Archaeological Survey Report
No. 62: 5-122. Berkeley.
Heizer, R. F. and J,E. Mills
1952   The Four Ages of Tsurai: A Documentary History of the Indian Village
on Trinidad Bay. University of California Press, Berkeley.
Mitchell, S. R.
1959
The Woodworking Tools of the Australian Aborigines. Journal of the
Royal Anthropological Institute 89: 191-199.
Phillipson, L. and D. Phillipson
1970   Patterns of Edge Damage on the Late Stone-Age Industry from
Chiwemupula, Zambia. Zambia Museums Journal 1: 50-75.
Shafer, H. J.
1970
Tindale, N. B.
1941
Notes on Uniface Retouch Technology. American Antiquity 35(4):
480-487.
The Hand Axe Used in the Western Desert of Australia. Mankind 3(2):
37-41.
35
Waterman, T.T.
1920
Yurok Geography. University of California Publications in American
Archaeology and Ethnology 16: 177-314.
Wuertele, E.
1973 The Experimental Use of Stone Tools in Woodworking. Unpublished
manuscript; on file, University of Texas at San Antonio.
36
-43
0
4bD
0
0 0    0~~~~~~~p
0   C.)0
z g .
00
U  t4  E-
Cd
S     Q)
0 -4
*Cd .Fe
0  i
_,  X
4, o a4
z
0
LL
I
u
0
-J >.
Oi~-
m z
I O
_
4)
,r4
X
ro
Ca
ro
. 0.4
;3 cd
.r4 M
k
E-A
37
a
o a:
0~
e                             ~~~~~~~~~~~~~~~~~m , O
QY    -4~
cdI
54 C
0~~~~~~~~~~~~~~~~~~~~~40
18 1 t1 Q^1~~~~~~~~~~~~~~~~~~~*-
(U
38
a
b
Figure 3. Unifacial Cobble Tools, Humboldt County, California. a, 1-72198 (Humn-118);
b, 1-90422 (Hum-129).
I
I
i
39
a
0      2      4      6     8      10cm
b
Figure 4. Unifacial Cobble Tools, Humboldt County, California.  , 1-90363 (Hum-126);
b  1-99149 (Hum-169).
Figure 5. Unifacial Cobble Tools,
Humboldt County, California.
a, 1-99142 (Hum-169); b, 1-72181
(Hum-126); c, 1-115863 (Hum-169).
0      2     4      6      8      1Ocm
__                            _ o--
40
a
b
c
41
d
1      2  3  4   5 CM
Figure 6. Unifacial Cobble Tools,
Humboldt County, California.
a, 1-72095 (Hum-126); b, 1-98837
(Hum-169); c, 1-98668 (Hum-169);
d, 1-98666 (Hum-169); e, 1-90427
(Hu-m-120).
C
e
42
O   1   2   3   4   5 CM
a
b
Figure 7. Unifacial Cobble Tools, Humboldt County, California. a, 1-98805 (Hum-169);
b, 1-90386-3 (Hu;m-126).
43
a
b
Figure 8. Resharpening Methods Observed on Unifacial Cobble Tools, Humboldt County,
California. a, removal of nibbled (step-fractured) edge by removal of flakes from dorsal
face; b, removal of dulled edge by detaching flake from ventral face.