In addition to the loom weight fragments described in an earlier post (Prehistoric Textile Production, September 5^th, 2022) eight porous stone artifacts recovered from the surface and upper portions of the archaeological deposit at Ohlendorf are also of particular interest (Figure 1, Table 1).  The objects are primarily shades of grey, yellow-brown, and pink, and are characterized by abundant surface vesicles, rough texture, and very low density.  The largest of the stones, recovered from the upper 40 cm of the site deposit, is very low density and floats on the surface of water.  None of the other pumice-like stones floated, but this could be related to the filling of the smaller near-surface vesicles with heavier soil particles and sand grains.  One of the artifacts had a deep longitudinal groove on one side and all the artifacts, most of which seemed to be fragments, had evidence of use as hand-held abraders.  The abrasive stone was apparently employed in weapon shaft and bone tool manufacture, hide preparation, and was occasionally carved into pipe bowls and pendants.  This distinctive raw material, which we initially considered to be pumice stone, is uncommon in the locale of investigation and has not, to our knowledge, been previously described as part of Late Mississippian assemblages in the northern Nodena phase area (but see Morse 1989:Figure 9l).  At Banks Village (3CT13), 40 km southwest of Ohlendorf near Lake Wapanocca, Perino (1966:55; Figures 17 and 24) recovered several abraders and a bead-like object that we believe are the same raw material (the illustrated “floatstone” abrader from 3CT13 is 6.0 cm long). 

Table 1.  Ohlendorf (3MS796) vesicular stone artifacts.

Color	L, mm	W, mm	TH, mm	Vol, cubic mm	Mass, g	Density, g:cubic mm
dark gray	64.6	47.3	36.6	111834.2	42.7	0.000382
grayish brown	41.4	28	23.3	27009.4	15.8	0.000585
dark gray, grayish brown	49.9	31	16.3	25214.5	18.4	0.00073
pink	48.1	30.6	14.2	20900.4	15.5	0.000742
grayish brown	30.5	23.8	20.2	14663.2	11.2	0.000764
dark gray	23.2	23.7	16.4	9017.4	7.2	0.000798
dark gray, very pale brown	45.4	24.8	20.1	22631	18.8	0.000831
gray, yellow-brown	69.5	33.2	28.4	65530.2	57.6	0.000879

Identical artifacts have been described on numerous archaeological sites to the north and northwest of Ohlendorf along the Missouri River drainage between South Dakota and the confluence of the Mississippi River (Estes et al. 2010; Stephenson 1971:69, Plate XXXIIa-e).  Referred to more correctly as paralava, this porous light-weight stone occurs where naturally combusted near-surface coal seams have baked and physically modified surrounding sedimentary materials.  Subsequent erosion washes chunks of the paralava into regional drainages, where some of it travels downstream as low-density “floatstone” and accumulates with driftwood and other light-weight materials on islands and bars along the channel (see discussion by Perino 1966:55).  A large paralava outcrop is mapped in southwestern North Dakota and eastern Montana, where the main upper Missouri River tributaries (Cannonball, Heart, Yellowstone, and Knife Rivers) cut through the metasedimentary surface exposures.  Volcanic sources of igneous pumice and tuff also outcrop farther upstream in Wyoming, Montana, and Idaho, but physical and chemical analysis of vesicular artifacts from the Leary site in southeastern Nebraska indicated clearly that they are made of metasedimentary paralava rather than true volcanics (Estes et al. 2010:75-76).

No chemical analysis of the Ohlendorf vesicular artifacts was performed, but several lines of evidence strongly suggest that this material is also paralava and was probably collected locally as “floatstone” from driftwood dams and sand bars along the main channel of the Mississippi River, located only about two km east of the site.  The qualitative color range of the abrasive stone artifacts from Leary and Ohlendorf is the same (cf. Estes et al. 2010:72 and Table 2), and the density of the material as calculated from the arithmetic means of the quantitative ranges of the two samples is essentially identical (Table 2; unit is g per cubic mm).  Furthermore, the Ohlendorf artifacts are about 20–28 percent smaller than the Leary sample (n = 13), which is within expectations given the gradual reduction in size due to stream-action erosion as a direct function of distance from the source outcrop.  In fact, the maximum size of the Ohlendorf artifacts is quite accurately predicted by a simple linear distance-decay function which can be generated from data provided by Estes and colleagues (2010:77), who state that the maximum dimension of paralava artifacts from the Steed-Kisker sites is 9.5 cm compared to 9.81 cm at Leary, located ca. 92 km (straight-line distance) upstream (reduction of 0.00337 cm/km).  Ohlendorf is in turn about 765 km downstream from Steed-Kisker and should thus exhibit a maximum artifact dimension of 9.5 – [(0.00337)(765)] = 6.92 cm.  The longest artifact found at Ohlendorf was 6.95 cm (Table 2, column 3, bottom).  At Potts Village (ca. AD 1550–1700), located upstream 700 km north-northwest of Leary along the Missouri River just south of the paralava outcrop, Stephenson (1971) recovered 44 “scoria” specimens with a maximum dimension of 10.5 cm, somewhat less than the value of 12.1 cm predicted by the linear function.

Table 2.  Quantitative comparison of Ohlendorf and Leary site paralava artifacts.

Site	Mass, g	L range, mm	W range, mm	Th range, mm	Mean density
Leary (25RH1)	2.7-152.2	30.0-98.1	16.2-72.2	9.9-59.6	0.000787
Ohlendorf (3MS796)	7.2-57.6	23.2-69.5	23.7-47.3	14.2-36.6	0.000775

Apart from the Banks Village specimens reported by Perino (1966:55), we are unaware of similar paralava artifacts in regional assemblages of the late prehistoric Nodena, Tipton, Walls, or Horseshoe Lake phases.  A vesicular grooved abrader with a maximum dimension of 5.8 cm from the Upper Nodena site (Morse 1989:Figure 9l) may also be paralava, but no detailed discussion of the raw material accompanies the artifact plate.  “Pumice abraders” have been identified very near the Mississippi River in the Cairo Lowlands at the chronologically earlier Weems and Hoecake sites (Williams 1974).  No dimensions or illustrations of the artifacts are included in the site report, but the linear function described above predicts that these artifacts should be slightly larger than the Ohlendorf specimens, with a maximum dimension of about 7.35 cm.  As pointed out in the excellent article on this distinctive material class (Estes et al. 2010:77), early observers such as George Catlin recognized that paralava was likely located “in every pile of driftwood from [the outcrop] to the ocean,” so it is assumed that these artifacts are under-reported in the technical literature, particularly from archaeological sites very near the main Mississippi River channel below the mouth of the Missouri.  While paralava is documented from sites as early as the Archaic horizon, it seems to be more prevalent on very late prehistoric sites.  Ohlendorf, with three calibrated median radiocarbon dates between AD 1419 and 1568, further reinforces this temporal trend (Buchner et al. 2022).

References Cited

Buchner, C.A., M.R. Childress, J. Rossen, and A. Baer. 2022. Phase I Cultural Resources Survey of the 2401.79-Acre Exploratory Ventures LLC Proposed Project in Mississippi County, Arkansas.  Commonwealth Heritage Group/Panamerican Consultants, Memphis, Tennessee.  Submitted to the U.S. Army Corps of Engineers, Memphis District.

Estes, M.B., L.W. Ritterbush, and K. Nicolaysen. 2010. Clinker, Pumice, Scoria, or Paralava?  Vesicular artifacts of the Lower Missouri Basin.  Plains Anthropologist 55(213):67–81.

Morse, D.F. (editor). 1989. Nodena: An Account of 90 Years of Archaeological Investigation in Southeast Mississippi County, Arkansas.  Arkansas Archeological Survey Research Series No. 30 (second edition).

Perino, G. 1966. The Banks Village Site, Crittenden County, Arkansas.  Missouri Archaeological Society Memoir No. 4, Columbia. 

Stephenson, Robert L. 1971. The Potts Village Site (39CO19), Oahe Reservoir, North Central South Dakota.  The Missouri Archaeologist 33:1–140.

Williams, J. R. 1974. The Baytown Phases in the Cairo Lowland of Southeast Missouri.  The Missouri Archaeologist 36:1–109.