STRATIFIED PREHISTORIC SITES ALONG THE C&O CANAL

Stuart J. Fiedel

Louis Berger Group

Stephen R. Potter

National Park Service

Society for American Archaeology 2004

From 2003 through 2005, the Cultural Resource Group of the Louis Berger
Group, under contract to the National Park Service (NPS), National
Capital Region, undertook a three-year program for the identification
and evaluation of archeological resources within the lower 59-mile
segment of the C&O Canal National Historical Park, which extends along
the Potomac River from Georgetown to Sandy Hook, just east of Harpers
Ferry. This work was intended to implement the Systemwide Archeological
Inventory Program for the park. Geoarchaeological testing and
archaeological surveys resulted in identification of 16 new sites and
relocation of 14 previously known sites. We are currently performing a
comparable investigation of the 59 to 123-mile segment of the park.

We had great success in discovery of deeply stratified prehistoric sites
on the floodplains of the Potomac, which was a primary research goal.
Unlike the ubiquitous shallow plowzone sites in Piedmont uplands, where
cultural remains from the past 13,000 years are inextricably jumbled
together, these are classic layer-cake formations, where sterile
river-laid sediments separate discrete episodes of human occupation. The
deeply buried remains of camps and villages have never been disturbed
either by later prehistoric inhabitants or by historic and recent
farmers. As Joffre Coe declared in 1964, it is imperative that we find
and investigate such sites, "since that is where the answers lie to the
problems of early cultural developments in the eastern United States.

On the Potomac River, very few deeply stratified sites have been
investigated previously. But, surface finds of fluted points and later
Archaic artifacts in the Potomac drainage demonstrate a continuous human
presence in the region since 13,000 cal BP. Several well-known Eastern
Paleoindian sites are quite extensive\--over 300 feet long. Paleoindian
sites along the Potomac are likely to include similar large camps,
comparable in scale to later Archaic communities. Thus, on the
optimistic assumption of the survival of intact floodplain sediments of
requisite age, we hoped that, with an intelligently designed systematic
survey strategy and some dumb luck, we could discover deeply buried
sites from the 9000 years preceding the Terminal Archaic.

Berger's geoarchaeological consultant for the C&O Canal project was Dan
Wagner. Using a 3-inch auger, Wagner was able to sample alluvial
deposits to a depth of about 11 feet. But with almost 60 miles of
riverbank to cover, we had to develop a strategy for efficient testing
of selected locations of highest potential. For this, we turned to
Joffre Coe's pioneering research in the Roanoke River basin. Coe
concluded that, in Fall Zone river valleys, early Holocene sites would
be found at locations with specific characteristics:

1\) a narrow valley forms a funnel neck where there was limited space
for a campsite

2\) In narrow and rocky valleys, the high velocity of the water
prevented the development of mature meander patterns, and

3\) Fingers of resistant rock extend from the valley wall to the edge of
the river. Behind these projecting rocks, the river forms large eddies
when it is in flood and deposits sand and silt at a faster rate than
elsewhere along the narrow flood plains. Eventually these deposits
become higher than the normal flood level.

Coe also observed that deep alluvial deposits containing stratified
sites may occur where a river confluence, located just above the
narrowest point in the valley, creates eddies. Michael Stewart
(1991:100) similarly attributes the preservation of the Paleoindian zone
at Shawnee-Minisink to slackwater deposition as a result of the
hydraulic dam effect common at stream junctions" where "The velocity of
a tributary stream with a low to moderate gradient is slowed
dramatically when it junctions with the river in flood, moving at a
greater velocity. This decrease in energy causes the tributary to dump
its sediment load."

Based upon a preliminary examination of USGS topographic maps, and with
Coe's model in mind, we selected 14 extensive floodplains for
geoarchaeological reconnaissance. Selection of particular locations for
auger tests was aided by our discovery, in the Library of Congress, of
very detailed maps drawn for the US Army in 1865. These showed small
tributary streams which are not depicted on the modern maps.

Wagner tested 12 floodplains, with a total of 23 auger tests. Seventeen
of these tests produced stratigraphic sequences with multiple buried
A-horizons that indicate the past availability of stable surfaces for
human occupation. Only one of the 12 tested floodplains had no buried
A-horizons. In 13 of the 23 auger tests, Wagner recovered charcoal or
encountered fire-cracked rock that provided unambiguous evidence of
human occupation. Based upon soil weathering, he believed that the
deepest A-horizons in 4 floodplains date from the Early to Middle
Holocene; 3 are Middle Holocene; 1 is Mid- to Late Holocene, and 2 date
from the Late Holocene. Based upon soils alone, Wagner was convinced
that the deepest strata at the Tuscarora Creek confluence dated from the
Terminal Pleistocene to Early Holocene.

These stratified sites have generally been found where smaller streams
flow into the Potomac. At seven such confluences, inspection of bank
exposures---where the meandering tributary streams continue to eat away
the old levees and alluvial fans\-- confirmed that cultural deposits
were associated with the buried surfaces.

Now, it is obvious that one reason for the dearth of investigations of
deeply buried sites is that they are not only hard to find but also
difficult to adequately and safely expose. Once you get below 5 feet,
OSHA standards for trenching require very extensive lateral excavation
to open relatively small deep holes. Stepped excavation of stream
cutbanks proved to be an expedient approach to sampling the deep
cultural deposits at Broad Run and Tuscarora Creek.

Excavations at Broad Run showed that the lower of two A-horizons there,
lying about 7 ft below surface, dates from the Late Archaic. Several
typical diagnostic artifacts of the Savannah River Broadspear complex
were found within this deposit. Stone tools from this zone were
associated with abundant, well preserved charcoal, including carbonized
nutshells. Charcoal from this zone has been dated to about 4200 cal BP
*\[3800+-40 rcbp, 4290 to 4080 cal BP (Beta-187616)\].* The upper
A-horizon at Broad Run, about 1.5-2 ft below surface, yielded Late
Woodland artifacts (ca. AD 1200-1500) such as potsherds.

![](media/image1.wmf){width="4.995833333333334in"
height="3.7472222222222222in"}

Excavations at the mouth of Tuscarora Creek revealed a four-horizon
cultural sequence: Late Woodland at the top, Early Woodland about 3 ft
below surface, a very faint late Middle to Late Archaic horizon at about
5.7 ft, and an Early Archaic and/or Paleoindian zone at ca. 7 to 8 ft
below surface. The Early Woodland zone can be dated to about 3000-2500
rcbp, based upon the ceramic sherds recovered: sand- and quartz-tempered
Accokeek sherds, steatite-tempered and cord-marked Selden Island sherds,
and Marcey Creek ware, steatite-tempered, flat-bottomed, and lacking
cord-marks. The Middle Archaic zone produced almost no artifacts, but a
distinct feature with charcoal, FCR, and calcined bone flecks dated to
about 5800 cal BP \[*5110+-40 rcbp, 5740-5930 cal BP (Beta-187613)*\].
The lowest zone lacked unambiguously diagnostic artifacts.

![](media/image2.wmf){width="4.995833333333334in"
height="3.7472222222222222in"}

Wagner found a jasper flake and rhyolite point at about 7 feet; we
suspect that the point is Middle Woodland, from a slumped deposit. The
tip of a broken late stage biface made of fine-grained grey quartzite,
was found during excavation at 6.95 ft below surface. Unfinished and
lacking a base, this biface is not typable. A point base fragment was
recovered from the screen during excavation of level D23 (7.7 to 8 ft
below surface). It is made of black chert, and represents one corner of
a corner-notched, convex-based point, with a ground basal margin. We
were excited by recovery of lithic debitage comprising materials rarely
seen in typical Archaic and Woodland assemblages. A tan or amber,
translucent chalcedony or jasper appeared to be the same stone that was
used to make a spurred endscraper, which was a surface find from 18MO10,
the Patton Turf Farm site, about 10 miles downstream. This scraper is
presumably a Paleoindian tool, so we thought there was a good likelihood
that we were dealing with a Paleoindian component at Tuscarora Creek. On
the other hand, the deep zone assemblage included, besides the yellow
and red jasper, translucent chalcedony, and grey and black chert, quartz
and a considerable amount of rhyolite, which seemed inconsistent with a
Paleoindian attribution. And then there was that point fragment....
Although it was too small to be definitive, it resembled the Kirk-like
points found by Broyles (1971) in one of the deepest cultural zones
(Zone 36) at the St. Albans site. A hearth in that zone was
radiocarbon-dated to 9850+-500 rcbp, and we guessed that the Tuscarora
Creek material would be of comparable age. In fact, we soon obtained two
AMS radiocarbon ages on charcoal fragments: 9290+-40 rcbp (10,280-10,570
cal BP) and (from two inches deeper) 8360+-40 rcbp (9270-9470 cal BP)
(*Beta-187614 and 187615*).

Still, we wondered if the deep zone might be a compressed multicomponent
accumulation of both Early Archaic and Paleoindian elements. So, we
opened another 2.5 by 5 ft unit on the cutbank in the next field season.
This excavation yielded more jasper and chalcedony flakes. Again, no
diagnostic points were found, but we did find a spokeshave on a red
jasper blade-like flake, which had us thinking about Paleo again.
However, just below the concentration of cryptocrystalline debitage, we
found a pebble chopper. Such tools are never found in Paleoindian
assemblages, but they occur in association with Kirk Corner-notched
points at several sites in the Mid-Atlantic and Northeast, with dates of
about 9500 rcbp. So, putting all the evidence together, we conclude that
this is a single-component Early Archaic campsite, dating from 10,500
cal BP. Now, note that all of this material was situated just above a
cobble lens. We suspect that these cobbles represent an Early Holocene
scouring episode by the Potomac, the same event that Al Goodyear has
documented in many other Southeastern river valleys. It may be a marker
of the end of the Younger Dryas at 11,550 cal BP, when there was an
abrupt increase in temperature and probably also in rainfall and
consequent erosion of denuded landscapes.

We close with a few thoughts about the implications of these stratified
sites for Cultural Resource Management. Having been identified and, to
some degree, delimited, the sites can be protected by park personnel
against looting or destruction by proposed development. However, the
same erosional processes that have exposed the bank cuts, allowing
access to the deepest occupation zones, also threaten to destroy these
sites in the not too distant future. Section 110 of the National
Historic Preservation Act, as amended \[*P. L. 102-575*\], states that
each Federal agency shall ensure that historic properties under its
jurisdiction and which "may be eligible for the National Register are
managed and maintained in a way that considers the preservation of their
... archaeological ...values ... and gives special consideration to the
preservation of such values in the case of properties designated as
having National significance." Clearly, the deeply stratified sites we
have discussed are potentially eligible for listing on the National
Register, certainly at the regional level and perhaps at the national.
It is equally clear that the NPS, as part of its legal obligation under
NHPA and the 1916 Organic Act \[*P. L. 64-235*\] that established the
agency, must develop and implement a plan to stabilize these
archaeological sites in order to "conserve \[them\] ... for the
enjoyment of future generations."