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6.0 LABORATORY INVESTIGATIONS

6.1 OBJECTIVES

Upon completion of field investigations, recovered artifacts were transported to the Dames & Moore archeological laboratory in Bethesda, Maryland. They were cleaned, catalogued and analyzed according to the Virginia Department of Historic Resources State Curation Standards and the Secretary of the Interior? Standards and Guidelines for Curation, (36 CFR 79).

6.2 METHODOLOGY

In all, 655 historic, prehistoric, and organic artifacts were recovered from the Phase I shovel test survey of the Area of Potential Effect for the NASM. A total of 1,409 additional artifacts were recovered from the Phase II evaluation of the Pump Site. Most artifacts were gently washed using plain water and a soft toothbrush. Delicate and/or unstable materials, such as decayed metal and organic material, were carefully dry-brushed with a soft toothbrush. Plastic colanders were used in the wash basins to avoid the inadvertent mixing of artifacts.

After they dried, the artifacts were labeled and bagged according to provenience and type. Artifacts recovered from the eight sites were given acid-free paper labels with the state site number and catalog number. Isolated artifacts received an acid-free paper label with the catalog number. Each type of artifact in each stratum of every shovel test pit or Phase II unit was given a unique catalog number.

Artifacts larger than one-square inch were also labeled directly, unless they would be adversely affected by such treatment. Site and catalog numbers were written on a layer of Acryloid B-72 using India ink and a quill pen. Dark, opaque artifacts received an undercoat of white gesso before being labeled. When the ink dried, an overcoat of B-72 was used to seal the label. The artifacts and accompanying acid-free labels were then placed in 2-mil. polyethylene ziplock bags.

Artifacts from the same provenience and material (such as iron or glass) were bagged together. Label information was also written on bags with a permanent black marker. Bags were punctured to prevent condensation, with the exception of those containing iron objects. Iron objects were placed in sealed, unpunctured bags, in order to retain a stable environment and prevent further damage. Bags were then placed in archival quality acid-free Hollinger boxes for transport to the Virginia Department of Historic Resources in Richmond, Virginia.

6.3 ARTIFACT ANALYSIS

During labeling and bagging, the artifacts were cataloged and analyzed. The items collected were separated into artifact classes and non-cultural materials. Prehistoric artifacts included flake and shatter debitage, stone tools, and projectile point fragments; historic materials included nails, glass, ceramics, brick, iron and other metal, buttons, coins, and clay pipe fragments. Organic material included shell and charcoal. The artifact inventory is attached to this report as Appendix D.

Artifacts were analyzed to determine their approximate date of manufacture and their function. The date of manufacture allows the archeologist to determine the earliest possible date of deposit of the most recent artifact. This is called the terminus post quem (date after which). The average date is also ascertained for each deposit of artifacts found together to determine the approximate date range of the deposit. It is not possible to determine the date of all artifacts; those that are datable are called diagnostic artifacts. Diagnostic artifacts are items that were manufactured or popular in certain restricted time periods, such as decorated ceramics or glass and projectile points.

Artifacts are also analyzed to determine their probable date and function. They are sorted into use classes (domestic items or hunting items, for example). These classes of artifacts in turn reveal clues about the function of a site. Sometimes an archeological site is multi-component, that is it has artifacts or features that represent more than one occupation over time.

6.3.1 Prehistoric Artifact Analysis

Prehistoric cultural materials collected during the Phase I survey included lithic debitage (the waste chips produced as a by-product of stone tool manufacture), stone tools, projectile point fragments, and fire-cracked rock. Analysis of the lithic artifacts was conducted with the objective of identifying diagnostic artifacts. The great majority of the chipped stone material encountered was quartz or quartzite; a single chert flake and a single chalcedony flake were the only exceptions.

Lithic material included flakes, shatter, fire-cracked and heat-altered rock, scrapers, bifaces, and projectile point fragments. Decortication flakes (primary flakes produced during initial shaping of tools), and secondary or tertiary flakes (produced during the final stages of tool manufacture) were found. The majority of the lithic material found at Dulles Airport was shatter, debitage that may be produced during any stage of tool manufacture. Almost all lithic artifacts recovered were either quartz or quartzite; one chalcedony flake was found. One quartz projectile point appeared to date to the Archaic period, but because it was broken and not completely finished a more precise assignment to a cultural period was not possible. The survey also produced a quartz scraper, a quartzite scraper, and a quartz biface.

6.3.2 Historic Artifact Analysis

Historic artifacts were grouped into standard categories. The use of these categories allowed researchers to assess function and chronology in order to determine a site?s date of occupation and the activities performed there.

Function. Archeologists examined artifacts? functions to establish use patterns and the nature of sites. Artifacts may be domestic (items directly associated with household activities like food service and storage vessels, furniture items, and food remains), agricultural (material used in farming such as hoes and harnesses), industrial (items associated with extraction or production technology like slag, tools, and various metal objects), architectural (elements directly associated with buildings including brick, mortar, nails, window glass, cementing agents, and shingles), arms (encompassing all forms and varieties of weaponry), clothing (items such as buttons, snaps, belt buckles, shoes, needles, pins, scissors, and thimbles), personal (elements directly associated with individual use like coins, keys, tobacco-related artifacts, combs, brushes, and writing materials), or miscellaneous (items that have more than one possible function, or those that do not fit into any of the previous functional group classifications). Domestic, agricultural, architectural, clothing, and personal artifacts were recovered during the Phase I survey and Phase II evaluation, suggesting that the historic sites found were residential.

Chronology. Temporal affiliation of historic sites was primarily determined through analysis of ceramics, bottle glass, and nails. Ceramic sherds recovered during the investigation were initially classified into three groups based on material and manufacturing technique: earthenware, stoneware, and porcelain. Earthenwares, made from naturally occurring clays and fired at low temperatures, were further subdivided into refined, coarse, and/or utilitarian wares. Stoneware, a high-temperature fired clay, is used primarily for utilitarian forms such as jugs, bottles, crocks, and bowls. Porcelain, a highly vitrified ceramic composed of kaolin, silica and feldspar, includes fine table wares, vases, and miscellaneous ornamental pieces. Coarse and refined earthenware, stoneware, and porcelain were all found during the NASM project. Paste, manufacturing technique, and decoration were used to identify the ceramic ware type of the sherds recovered (e.g., creamware).

Ceramic sherds recovered during the fieldwork dated from the eighteenth through the twentieth centuries. The date range associated with a particular ceramic type represents the period when the ceramic type was most popular. The use of ceramic types as a method of dating is based on the observation that people?s taste in ceramics changes through time. From the eighteenth century through the present, changes in fashion have developed quickly, and a particular ceramic type can be assigned to a relatively short span of time. Historic merchant and manufacturer records aid archeologists in determining ceramic chronologies (Miller 1980, 1988; Worthy 1982). Temporal information for eighteenth century ceramic types is drawn primarily from the work of Noël Hume (1970). The nineteenth and twentieth century ceramic chronology is not as succinctly defined in one source. Changes in paste and glaze were gradual to accommodate shifting trends in the ceramic market. However, the simultaneous use of datable decorative designs on differing nineteenth century ware types has helped delineate a more concise ceramic chronology for this period.

Most bottle glass fragments found during the survey were so small that their precise form or date could not be ascertained. Color is an important attribute for dating glass but not always enough for a certain identification as many glass colors have been produced over a long period of time. Eight whole bottles or bottle necks were recovered from three historic sites investigated; additional bottles in the vicinity of Historic Site B were noted but not collected. Most of these bottles were mechanically produced, suggesting a manufacture date after 1880. Earlier bottle manufacturing types recovered included those with molded bodies and blown necks and lips. Two fragments of eighteenth century hand blown bottles were also recovered.

Archeologists looked at four primary attributes of bottle glass to establish date ranges: mold type, finishing techniques, bottle form, and color. Technology for mold-produced bottles has existed for centuries. However, not until the seventeenth and eighteenth centuries, when hinged metal molds were developed, did mold-blown bottles begin to replace free blown bottles (Munsey 1970). Use of these molds did not become widespread until the early 1800s. At this time, the pace of technological advancements increased dramatically in many areas of the glass manufacturing industry. Development of shoulder and full height molds, new methods for holding bottles during the process of hand blowing, and improved finishing techniques were primary areas of advancement.

During the late nineteenth century, glass container manufacturing became progressively more mechanized, beginning with the development of semiautomatic machinery (circa 1880), and culminating with the introduction of a fully automated version (1903). The first successful implementation of a fully mechanized process was developed by Michael Owens; by the 1920s, his machines had become the primary bottle manufacturing method in North America. Each manufacturing process leaves distinctive marks on its products, allowing archeologists to identify and date them.

The identification of various nail types is useful in both temporal and functional analyses. There are three basic stages in the technological chronology of nails: wrought nails, cut nails, and wire-drawn nails. All three types of nails were recovered during archeological investigation of the NASM property, confirming the eighteenth through twentieth century date range suggested by the ceramics found. Hand-forged wrought nails were the primary construction material in the seventeenth and eighteenth centuries. While wrought nails still are manufactured today, they are used primarily for restoration and reproduction purposes. Their wide-scale use effectively ended with the introduction of machine cut nails (NoëlHume 1970).

Cut nails were introduced in the 1790s. These nails initially had a machine-cut body with a hand-made head. Not until technological advancements around 1815 had produced a totally machine-made version did they begin to replace wrought nails as primary construction fasteners (Noël Hume 1970).

Wire-drawn nails first were introduced into the United States from Europe around 1850. Early wire nails were used primarily for box construction; they were not adapted for building construction until the 1870s. Although cut nails are preferred by some builders today, they were replaced almost universally by the wire nail by the turn of the twentieth century (Noël Hume 1970).

The date range for each site identified during the Phase I and Phase II investigations of the NASM property was developed through looking at the date ranges of ceramics, glass, nails and other datable items like buttons and pipes together as a whole assemblage. This technique helped correct for anomalous items that seemed to be much earlier (possibly heirloom items or items used long after their manufacture date) or much later (intrusive material not originally used by the site inhabitants) than the rest of the assemblage. Artifact information from the individual sites is discussed in Chapter 7 and Chapter 8.


Introduction Chap. 2: Historic Preservation Compliance
Chap. 3: Project Area Description Chap. 4: Background Research
Chap. 5: Field Investigations Chap. 6: Laboratory Investigations
Chap. 7: Archeological Findings of Phase I Survey Chap. 8: Archeological Findings of Phase II Survey
Chap. 9: Summary and Recommendations Chap. 10: Bibliography
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