Introduction

For compliance projects, our office requests consultation with the designated Office of State Archaeology (OSA) Review Archaeologist to discuss appropriate methodologies prior to archaeological field investigations. The methodology standards outlined below are to be used for clarification and guidance but allow for exceptions based on various factors.

The field methodology guidelines are organized in three parts. The introduction provides information concerning definitions, qualifications, and special conditions. The second section differentiates forms of field investigation according to objectives, level of effort, and associated activities (i.e., monitoring, reconnaissance survey or due diligence, Phase I identification survey, Phase II evaluation/testing, and Phase III data recovery/mitigation or treatment). The third section provides standards and guidelines for undertaking and documenting fieldwork activities.

Definitions

Defining an Archaeological Site

According to the National Park Service (NPS), an archaeological site is defined as “the location of a significant event, a prehistoric or historic occupation or activity, or a building or structure, whether standing, ruined, or vanished, where the location itself possesses historic, cultural, or archeological value regardless of the value of any existing structure” (as defined in the ‘How to Apply the National Register Criteria for Evaluation’ portion of National Register Bulletin 36).

For the purposes of archaeological site identification, the OSA defines an archaeological site as a location where at least one artifact or feature greater than 50 years of age has been identified. All archaeological sites identified as a result of field investigations must receive a trinomial site number and require a completed OSA site form or cemetery form.

All materials – including artifacts, floral and faunal remains, and sediment samples, along with related documentation such as original field notes, maps, photographs, artifact inventory lists, and analysis forms – recovered and created for purposes of compliance with state and federal regulations shall be permanently curated in an approved archaeological repository, preferably in the state of North Carolina. Since archaeological investigations are inherently destructive and non-replicable, these guidelines ensure that collected artifacts and associated documentation from work done in the public interest will be available to future researchers.

Site Occurrence Probability Categories

The following site probability categories can be used to aid in the design of survey strategies. Thresholds for certain environmental variables used in classifying areas as high or low probability vary regionally and should be derived from previous survey data in the Site Record Inventory at OSA and in consultation with the OSA region review archaeologist. Contact information for the appropriate review archaeologist can be found at the OSA Contact page.

Low Probability – This designation typically applies to areas with poorly drained soils; and/or areas that are disturbed to such a degree that archaeological materials, if present, would lack sufficient integrity to be considered eligible for listing in the National Register. Areas identified as low probability through the inspection of topographic and soil maps should still be verified and documented in the field using visual inspection and subsurface testing, as appropriate. In many cases, it may be suitable to survey low probability areas at a reduced sampling interval.

High Probability – This designation typically applies to areas that provide low-cost resource access according to factors such as local geology, arable soil, water sources, ecological diversity, and transportation routes. Relevant factors will vary by region and expected site types. Archival and historic (deeds/parcel history) research should be done in advance of fieldwork to determine high probability areas where structures or activity areas are shown on historic maps (topographic, post office routes, soils maps, Sanborn maps, highway maps, etc.) and aerial images regardless of soil type or distance to water. Archival research can also be critical in defining potential for unmarked cemeteries or resources connected with underrepresented populations such as enslaved peoples.

Area of Potential Effects

According to 36 CFR 800.16(d), the Area of Potential Effects (APE) for a project is “the geographic area or areas within which an undertaking may directly or indirectly cause alterations in the character or use of historic properties.” In the case of archaeological sites, the APE is often the maximum area of potential ground disturbing activities (the area of disturbance) associated with a project, including permanent and temporary impacts. Certain undertakings, such as repairing the foundations of a historic building, may have a very limited APE, while others, such as the implementation of land management practices, may cover large areas. The Area of Potential Effects as originally defined for a project may change if it is re-designed.

Cemeteries and Grave Sites

According to North Carolina General Statute 65, Article 12, a cemetery is “a tract of land used for burial of multiple graves.” Cemeteries containing interments greater than 50 years of age should receive a trinomial site number. If the cemetery is associated with other historic site elements, or is located within a prehistoric site, it should be assigned a separate site number. A cemetery form should be completed with the cemetery site number; if other archaeological resources are present, they should be recorded on a site form with the separate site number. Given the possibility for unmarked graves in historic cemeteries, even burial locations with a single above-ground marker should be recorded as cemeteries.

Prehistory and History

Within these guidelines, archaeological sites are referred to as prehistoric, historic, or multicomponent. National Register Bulletin 36 defines prehistoric, or pre-contact, resources as “the archaeological remains of indigenous American societies as they existed before substantial contact with Europeans and resulting written records.” Bulletin 36 defines historic, or post-contact, resources as “sites and structures dating from time periods since significant contact between Native Americans and Europeans.”

There are a variety of terms that have been used interchangeably with prehistoric and historic. All of these designations can vary regionally based on when contact between Native Americans and Europeans began. When writing reports, time period designations should be used consistently and should be more specific whenever possible (i.e., describing a site as Early Woodland period rather than prehistoric).

Qualifications and Permitting

Principal Investigator Qualifications

Principal investigators of archaeological compliance investigations must meet the Secretary of the Interior’s Professional Qualification Standards as described in 36 CFR Part 61 and outlined in 48 FR 44716. For archaeology, minimum qualifications are:

• A graduate degree in archaeology, anthropology, or closely related field.
• At least one year of full-time professional experience or equivalent specialized training in archeological research, administration or management.
• At least four months of supervised field and analytic experience in general North American archaeology.
• Demonstrated ability to carry research to completion.
• A professional in prehistoric archaeology shall have at least one year of full-time professional experience at a supervisory level in the study of archaeological resources in the prehistoric period. A professional in historic archaeology shall have at least one year of full-time professional experience at a supervisory level in the study of archaeological resources of the historic period.

Archaeological Investigations on State Lands

If an area to be archaeologically investigated includes lands owned or leased by the state of North Carolina, excluding highway rights-of-way, the Principal Investigator must obtain an Archaeological Resources Protection Act (ARPA) permit from the State Archaeologist, according to the provisions of North Carolina General Statute Chapter 70, Article 2. Permits should be applied for well in advance of the anticipated fieldwork start date and require at least 30 days for issuance.

Permit applications can be obtained from the State Archaeologist, 4619 Mail Service Center, Raleigh, NC 27699-4619, or online from the OSA Permits page. A criminal background check by the State Bureau of Investigation is required for the Principal Investigator. Fingerprint cards and release forms can also be obtained from the State Archaeologist. While no fees are required to obtain the ARPA permit itself, a cost of $38.00 is required for the criminal background check. Certified checks or money orders for that amount, made out to the Office of State Archaeology, should be submitted with the fingerprint card, release form, and completed permit application.

Planning and Contingencies

Background Research

Prior to the fieldwork phase of a project, background research of previous investigations and previously recorded archaeological sites must be undertaken at the OSA. Records are updated constantly, so consultants must conduct a background research review before each new project to ensure that the most up-to-date information is used.

Access to archaeological site files, reports, and related documents is provided to qualified professional archaeologists and authorized representatives of federal, state, or local agencies and institutions whose purpose is to effect planning decisions regarding archaeological resources. Persons having access to site files will be expected to maintain the confidentiality of site location information in accordance with North Carolina General Statute 70-18.

Due to the number of researchers desiring access to the site files and the limited space and equipment available, appointments are necessary. See Part 1: Background Research for more information about background research at the OSA.

Background research should also include a thorough review of archival documents. Archival and historic (deeds/parcel history) research should be done in advance of fieldwork to determine high probability areas where structures or activity areas are shown on historic maps (topographic, post office routes, soils maps, Sanborn maps, highway maps, etc.) and aerial images. This research can be critical in assessing the likelihood that archaeological resources related to underrepresented communities may be present. It may be necessary to visit county clerk offices, local historical or genealogical societies, universities, or museums to gather all relevant information.

Changes in Field Strategies/Methodologies

Any changes in survey, testing, or data recovery strategies/methods should be undertaken only after consultation with the OSA review archaeologist.

Inadvertent Discovery of Human Remains

If human skeletal remains are encountered during archaeological investigations, the provisions of North Carolina General Statute Chapter 70, Article 3 apply. The State Archaeologist should be contacted immediately. Investigations can resume after contact has been made and the consultation process has been initiated. The Principal Investigator shall notify the State Archaeologist as to the cultural and biological characteristics of the remains as soon as such determination has been made. Consultation between the State Archaeologist and the Principal Investigator will determine where the remains will be held after excavation.

If the skeletal remains are determined to be Native American, consultation will be undertaken between the State Archaeologist and the Executive Director of the North Carolina Commission of Indian Affairs. If the skeletal remains are not Native American, the State Archaeologist will publish notice of the discovery in an effort to determine next of kin.

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Forms of Investigation

Monitoring

Objective

The goal of archaeological monitoring is to determine the presence or absence of archaeological deposits while ground disturbing activities are taking place. Archaeological monitoring is not a primary survey strategy, but it may be used in certain situations when deemed appropriate. For example, on-site monitoring of construction activities may be undertaken to ensure that a specific archaeological site, cemetery, or geographic area is not adversely affected by earthmoving activities.

Description

Ground-disturbing activities should be undertaken in such a manner that the monitoring archaeologist is able to observe excavations in real time and communicate with machine operators as work progresses. At the discretion of the monitoring archaeologist, ground-disturbing activities are halted if a suspected archaeological feature or deposit is encountered. The monitoring archaeologist should examine the exposed materials or feature and determine what additional work is necessary. In most instances, this will include recording locational data, photographing features and recovering archaeological remains.

The OSA review archaeologist should be consulted prior to the development and implementation of a monitoring strategy for those projects subject to Section 106, and a Secretary of Interior (SOI) qualified archaeologist must be present for all ground-disturbing activities to be monitored.

Reconnaissance Survey/Due Diligence

Objective

Reconnaissance surveys are systematic examinations designed to assess the potential for the presence of archaeological remains in a given project area. They are especially recommended as a means of acquiring information for planning intensive identification surveys of large areas. Based on the results of a systematic reconnaissance survey, it may be possible to divide a project area into zones of high probability or low probability based on the potential for sites to occur and to develop a more targeted Phase I survey. Reconnaissance survey reports should be reviewed by OSA staff for compliance before additional fieldwork is done.

Description

Reconnaissance surveys have two main components: a cultural resource assessment and field investigations. Cultural resource assessments summarize data from previously recorded sites in and near the project area and review the history and prehistory of a region to assess the potential for various archaeological site types. This should include intensive archival and historic deed research. Geological and ecological conditions in the project area relevant to the distribution of archaeological sites should also be considered through reference to data such as soil maps and LiDAR.

Reconnaissance field investigations entail systematic pedestrian reconnaissance and judgmental shovel tests to document the extent and types of ground cover and soil conditions. Sufficient documentation during a reconnaissance survey may eliminate the need for further field investigations in low probability areas based on various factors, such as disturbance or wet conditions and poor soil drainage. Exploratory subsurface excavations made to examine soil profiles, such as shovel tests and cores, should be carefully documented with regard to their location, means of excavation, depth, characteristics, and contents.

Phase I Identification Survey

Objective

The goals of a Phase I archaeological survey are to identify archaeological sites, define their boundaries within a project area, and provide National Register of Historic Places (NRHP) eligibility assessments for all identified sites (if possible at this stage without a formal Phase II Evaluation/Testing). The assessments are presented in the survey report as recommendations (e.g., not eligible, no further work recommended; portion within project area not eligible; unassessed, additional work recommended; eligible, recommend avoidance; etc.). If a site extends outside of the boundary of the project area, an NRHP eligibility recommendation should only be made for the portion of the site that was actually investigated. NRHP eligibility assessments should also be made for any previously recorded site or portion of a previously recorded site in the project area that was formerly unassessed.

Description

Phase I surveys have two main components: a cultural resource assessment and field investigations. Cultural resource assessments summarize data from previously recorded sites in and near the project area and review the history and prehistory of a region to assess the potential for various archaeological site types. This should include intensive archival and historic deed research. Geological and ecological conditions in the project area relevant to the distribution of archaeological sites should also be considered through reference to data such as soil maps and LiDAR.

Subsurface investigation through systematic shovel testing is the most commonly employed Phase I survey strategy. Systematic pedestrian reconnaissance can be used to investigate areas where subsurface testing is infeasible. Limited test unit excavations might be employed to determine if features are present on identified sites. In certain depositional environments, Phase I investigations may also include remote sensing, stripping, and/or deep testing. Detailed guidelines for undertaking these activities are presented in Field Methodologies below.

Phase II Evaluation/Testing

Objective

The primary goal of Phase II evaluation/testing is to render a definitive determination of NRHP eligibility. If a site is recommended as eligible for listing in the NRHP as a result of Phase II investigations, the project archaeologist should evaluate potential adverse effects to the site, both direct and indirect, resulting from any undertakings that might damage its integrity. The Phase II work should collect enough information to provide specific recommendations regarding mitigation activities, including a research design that identifies the datasets that would be created as a result of data recovery and the questions these data could be used to answer.

Description

All methods employed during Phase II evaluation/testing should be directed toward achieving the primary goal discussed above. These methods should focus on documentation of site integrity (intra-site structure and subsurface integrity) and assessment of site significance. This is, again, a two-part process with field investigations and contextual research.

Field investigations usually consist of sets of close-interval shovel tests and larger, formal excavation units. The primary focus of unit excavation should be to document and evaluate features and/or culturally derived stratigraphy, and the number and placement of test units should be adequate to provide definitive information regarding site integrity.

Geomorphological analysis should also be considered at this step to provide important insights on site formation processes and site integrity. Remote sensing, mechanical stripping, and specialized analyses (e.g., soil micromorphology, radiometric dating) may be necessary to assess NRHP eligibility.

The cultural resources research for a Phase II evaluation requires a literature review directed specifically toward assessing the current state of knowledge concerning sites like the one being evaluated. Without this contextual information, it is not possible to judge whether a site might possess the potential to provide important information about the past.

Phase III Data Recovery/Mitigation or Treatment

Objective

The primary goal of Phase III data recovery is to mitigate the adverse effects of a given undertaking on a NRHP-eligible archaeological site. In the case of data recovery, this is achieved by conducting excavations to obtain information commensurate with the site’s potential to address specific, formal research questions, and thereby produce, as per NRHP evaluation criterion D, information important to the understanding of history or prehistory.

Phase III data recovery is implemented when all other options, including avoidance and/or preservation, are deemed infeasible for a site or project area. After a formal finding of adverse effects is made, it is necessary to estimate the level of effort required to adequately mitigate adverse effects and fully address all research questions posed for the project. A Memorandum of Agreement (MOA) among the lead federal agency, State Historic Preservation Officer (SHPO), other agencies and/or consulting parties may be required prior to the development of a detailed data recovery plan and field investigations.

Under Section 106, Phase III work is undertaken with the understanding that excavation itself will destroy or significantly alter the integrity of a given site or portion of a site. As a result, after data recovery the mitigated site or portion of a site will no longer be considered eligible for listing in the NRHP.

Description

All methods employed during Phase III data recovery should be directed toward achieving the primary goal discussed above and should focus on collecting datasets to address specific research questions. Research questions should be formulated based on the results of Phase II or other site assessments. Data recovery is generally accomplished by excavating formal test units across the site, often as a set of horizontally-expansive blocks. Excavation may include mechanical stripping to expose features or other cultural deposits.

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Field Methodologies

Remote Sensing and Geophysics

There are various types of remote sensing techniques, which can be used to help “gather background environmental data, plan more detailed field investigations, discover certain classes of properties, map sites, locate and confirm the presence of predicted sites, and define features within properties” (see the National Park Service’s notice regarding the Secretary of the Interior’s Standards and Guidelines for Archaeology and Historic Preservation). Remote sensing covers all techniques other than excavation and physical inspection methods to observe and record visual, electromagnetic, or other geophysical properties on or below the earth’s surface. Remote sensing techniques include soil resistivity, proton magnetometer, gradiometer, ground penetrating radar (GPR), and various photographic techniques (aerial, infrared, etc.).

Although remote sensing techniques are, under certain conditions, an effective and efficient means to obtain information about the size, frequency, and distribution of subsurface archaeological features, geophysical methods typically do not allow for the full characterization of anomalies without direct archaeological investigation, i.e., ground-truthing. By the same token, systematic surface collection and traditional subsurface testing (shovel-testing) are poor sampling techniques for identifying most types of archaeological features and determining their distribution. When used together, remote sensing and traditional archaeological survey techniques can provide a more robust approach to the Phase I survey and site identification process. The feasibility and applicability of remote sensing surveys should be seriously considered at all stages of archaeological investigation.

Although the operation of geophysical equipment is mostly standard across disciplines, considerable expertise is necessary to effectively design, conduct, and interpret geophysical surveys of cemeteries and archaeological sites. Interpretation of the data and classification of geophysical anomalies must be done by, or under the direct supervision of, a qualified professional with demonstrated experience applying this technique to archaeological resources in the eastern United States.

Whenever a remote sensing survey is conducted, appropriate reporting should include documentation of the following:

• Semi-permanent datum points recorded using a GPS receiver with sub-decimeter accuracy that mark the geophysical grid corners or survey boundaries.
• Any anomalies selected for ground truthing. It is recommended that a representative sample of geophysical anomalies of archaeological interest be ground-truthed via soil coring and/or hand excavation (does not apply to cemetery contexts). Systematic ground truthing may be more appropriate during the Phase II testing phase or determined unnecessary in certain circumstances where previous testing has already occurred, or in historic contexts where detailed mapping/records may exist (e.g., Sanborn maps).
• Detailed discussion of the instruments used, how the data were collected, post-processing software used, and what specific processing steps were taken must be included in the report.
• Pertinent environmental, soil, and weather conditions during data collection, including dielectric value of the soil (or Relative Dielectric Permeability [RDP]) for GPR.
• Anomaly/target IDs, descriptions, and interpretations.
• Scaled maps with relevant site landmarks and/or datums visible and showing the distribution of anomalies and images/figures showing representative examples of survey results, including radargrams, amplitude slice maps, other gridded data, etc.

Metal Detection Surveys

Systematic metal detecting can provide information for developing recommendations of National Register eligibility for historic period sites during Phase I surveys by providing information on 1) site dates, through recovery of datable objects (e.g., nail types); 2) artifact diversity, and thereby site function; 3) artifact distribution, and thereby site size and organization; and 4) artifact clustering, which may relate to intact features or other deposits below the plow zone. If these types of information would be helpful in completing the National Register assessment of a historic period site during a Phase I survey, then systematic metal detecting is recommended.

A survey grid should first be established and tied into a site datum, and the datum should be mapped, preferably with GPS technology. Coverage should be systematic within the study grid. Metal detecting study lanes should be no wider than 1.5 meters (5 feet) in order to ensure adequate coverage. The vegetation or leaf litter may need to be removed within study lanes in order to effectively sweep the metal detector across the ground surface. All metal detector ‘hits’ should be flagged, numbered, and mapped. A sample of hits should be examined through excavation. Notes should be maintained on each of the ‘hits’ that are investigated, which should include at a minimum the following information: site number (if applicable), date, project number, what the object was, depth of object, and whether it was retained or discarded.

Remote Sensing for Cemetery Surveys

Although GPR is the preferred survey method for documenting cemeteries in North Carolina due to its non-invasive approach, other remote sensing techniques, such as magnetometer, electrical resistivity, and electromagnetic conductivity (EM) may provide complementary or even better results depending on site conditions. Specific survey parameters for doing cemetery work will depend on the instrument and the soil conditions within the cemetery, but there are a few method-specific guidelines for minimum standards:

When clearing the survey area of vegetation and brush, care should be taken to avoid damaging grave markers or disturbing any shrubbery, flowers, plants, or other articles planted or placed within the cemetery to designate where human remains have been interred.

All ground penetrating radar surveys in cemeteries should involve the collection of radargrams and the later processing of that data into three-dimensional volumes for creating amplitude slice maps. Graves can appear in radar data as positive or negative (gaps in an otherwise strong reflector) anomalies. Real-time flagging of hyperbolas in radargrams visible on the radar system display screen is highly discouraged if it is the sole survey result because tree roots (among other things) look very much like graves in radar profiles; furthermore, grave shafts might be located between hyperbolas, which is only visible in amplitude/time slice maps. Historic graves can present as subtle reflections and identification requires careful analysis by experienced personnel who are familiar with both the cultural context of the cemetery and interpreting GPR results in a cemetery setting.

Because graves can be relatively small, radar data in cemeteries should be collected along transects spaced no more than 50 cm apart (25 cm spacing recommended). GPR survey transects should ideally be oriented to cross perpendicular to the long axis of observed graves (if graves are oriented east-west, GPR transects should run north-south, if possible). Radar antennas with central frequency ranges from 200-700 MHz are recommended. Lower frequency antennas may be too low in resolution to differentiate side-by-side graves. Most soils in North Carolina rapidly attenuate radar energy, so depth penetration typically does not exceed two meters, unless soils are sandy. Radar surveys in cemeteries typically detect grave shafts (the soil within the grave), roads/paths, building and wall (outer walls, plot boundaries) foundations, utility lines (e.g., irrigation), and burial containers (coffins and vaults) if the depth of penetration is sufficient. If possible, GPR surveys should include a minimum of 10 meters beyond the observable cemetery boundary to investigate the potential for unmarked burials.

Pedestrian Reconnaissance

Systematic pedestrian reconnaissance is an acceptable method of survey in recently plowed or disked fields that have a surface visibility of fifty percent or greater. It may also be used as a first step to assess field conditions in areas that have a surface visibility of less than fifty percent. Systematic pedestrian survey should be conducted at an interval no greater than 10 m.

Systematic pedestrian reconnaissance survey should be supplemented with subsurface investigations, especially when the surface visibility is less than fifty percent. Shovel tests may be excavated at an expanded interval, depending on the field conditions. Shovel tests should also be excavated in areas possessing particularly high probability for archaeological sites regardless of surface visibility.

Sites identified by pedestrian survey in areas with surface visibility of fifty percent or greater should be investigated with shovel tests at a density of no less than 4 per acre, which is roughly comparable to excavating shovel tests at 30-meter intervals on transects spaced 30 meters apart. Since the purpose of the shovel tests is to assess the nature of subsurface deposits at the site, they should be evenly distributed to provide a representative sample. If clustering is apparent in the surface distribution of artifacts, additional shovel tests should be excavated in areas of high artifact density to assess the likelihood of features or other intact archaeological deposits.

For some sites, a complete surface artifact collection may not be necessary to provide a recommendation regarding further work and NRHP eligibility. A sample of artifacts may be collected from a site, particularly on sites with dense surface scatters and/or those that have a large quantity of similar artifact types. An appropriate representative sampling method should be used. Material that is not collected should be described in at least general terms and the location included on the site map (see Documentation below).

Excavation

Shovel Testing

Shovel tests should be at least 30 cm in diameter and should be excavated either 10 cm into sterile subsoil or hydric soil or to a depth of one meter below ground surface, whichever comes first. The fill from each shovel test should be screened through 1/4-inch (6.35-mm) or finer hardware mesh. Notes should be kept on each shovel test documenting the shovel test location, soil stratigraphy using USDA soil descriptions, Munsell color codes, depth, and the presence or absence of artifacts (Figure 1). A representative sample of shovel tests should be documented with photographs. Artifacts collected from shovel tests should be bagged separately by shovel test, and separated according to the natural soil or cultural strata with which they were associated.

The standard shovel test interval should be no greater than 30 m and transects should be spaced no greater than 30 m apart. A smaller or reduced shovel test interval may be appropriate in areas with particularly high probability or potential for significant, intact archaeological deposits. Conversely, an expanded shovel test interval may be appropriate in low probability areas or when employed in conjunction with other survey strategies, such as systematic pedestrian reconnaissance. Staggered grid or transect arrangements are recommended. A staggered grid reduces the area in between shovel test locations, thus increasing the potential to capture smaller sites that may not be intercepted by a non-staggered grid.

If shovel test transects parallel the edge of the Area of Potential Effects (APE), the transect nearest the edge of the APE should be no further than half a standard shovel test interval as defined for the project from the edge of the APE. For example, if the shovel test interval used for a particular project is 25 m, the transects nearest the edges of the APE should be no further than 12.5 m from the edge of the APE. If the APE is 60 m wide and shovel tests are excavated at 25-m intervals, there should be three shovel test transects, and the transects nearest the edges of the APE would be 5 m from the edge of the APE. If shovel tests were excavated on only two transects, the distance from the transects to the edge of the APE would be 17.5 m, which is greater than half of a standard shovel test interval as defined for the project, and not deemed adequate coverage for a high probability area (Figure 2).

Radial shovel tests excavated to define site boundaries should be placed at a reduced interval no greater than half that of the standard interval (e.g., if the standard interval is 30 m, the radial shovel test interval should be no greater than 15 m). At least two negative shovel tests should be excavated in each direction along site margins to determine the extent of the site. Internal radial shovel tests or close-interval shovel tests may be appropriate on some sites, for example to better delineate areas of artifact concentrations, to further investigate soil conditions, and/or to better assess site significance.

Close-Interval Shovel Testing

While shovel tests are primarily excavated to locate sites and define site boundaries, close-interval shovel tests may be excavated to help define site integrity. This includes documenting soil stratigraphy, artifact counts and distributions, and the presence/absence of culturally derived features or stratigraphy.

Close-interval shovel tests should be placed no greater than 15 m apart, and when possible intermediate to tests previously dug to delineate the site. All shovel tests should be excavated and recorded as described above in Shovel Testing. They should be clearly marked in the field and placed on project maps, preferably using GPS technology.

Soil Coring and Augering

Soil coring and augering are useful for investigating soils to determine whether they are likely to contain intact cultural deposits, or to examine soil variation across a delineated site. Cores and augers can be used either judgmentally, as part of a reconnaissance survey, or systematically within a survey area or site. Coring and augering should not be used as a means of identifying sites but may be used to identify features within sites.

Augers are best used to examine soil conditions in areas where deeply buried deposits are possible due to alluvial, colluvial, and aeolian processes, since augers may be used to examine soils to depths beyond what is accessible through shovel testing. Notes should be kept on each auger test documenting soil stratigraphy using USDA soil descriptions and Munsell color codes, and auger test locations should be clearly marked in the field and placed on project maps.

Soil core probes 1/2- to 3/4-inch in diameter are appropriate for systematically assessing soil conditions across a site. If a systematic core survey is to be conducted, a study grid should first be established. The study grid should be tied into a datum, and the datum should be mapped, preferably with GPS technology. Coverage should be systematic within the study grid. Notes should be kept on each core documenting soil stratigraphy using USDA soil descriptions and Munsell color codes. A map showing the probing transects should be included in the resulting report.

If soil coring and/or augering are going to be used in a cemetery context, see Cemetery Delineation and Soil Probing and Augering below for cemetery-specific guidance.

Test Unit Excavation

The number and distribution of excavation units should be determined by the information collected from shovel tests or other survey methods, such as remote sensing. The number and placement of test units may vary according to site size, distribution of artifacts, and any features or cultural strata encountered during site survey and delineation activities.

Test units may vary in size based on the extent of site boundaries, topography, and soil conditions. The size of any one unit should range from a minimum of 0.5-m square to 2-m square, with 1 square meter considered the standard test unit size.

Units should be excavated in set arbitrary levels within natural stratigraphy, such as fluvial deposits. Arbitrary levels of 10 cm are typical. The thickness of excavation levels in cultural stratigraphy should vary according to the nature of the deposit. Where present, the plow zone can be excavated as a single level, regardless of thickness. Midden soils may be excavated in 10 cm levels, but thinner arbitrary levels (e.g., 5 cm) may be appropriate in areas with microstratigraphy, especially dense artifact concentrations, and/or unique depositional environments such as rock shelters.

The fill from each test unit should be screened by level through 1/4-inch (6.35-mm) or finer hardware mesh. Artifacts should be bagged separately by unit and level.

Photographs and a formal profile drawing should be made of at least one wall of each excavation unit. At a minimum, the base of excavation in each unit should be photographed. Ideally, the bottom of each level should be photographed. Notes should be kept on each unit documenting soil stratigraphy using USDA soil descriptions and Munsell color codes, level depths, features and disturbances, and artifact types and quantities.

A permanent site datum should be established that is easy to relocate, and it should be included on the site map and preferably mapped with a GPS device. All excavation units should be clearly marked in the field and placed on project maps, preferably using GPS technology. The site map should also include the site boundary, unit datums, surface features if present, and topography.

Feature Excavation

Prior to excavation, features should be photographed in plan view, characterized using USDA soil descriptions and Munsell color codes, and drawn to scale. Feature locations should be plotted on site maps and plans, preferably using GPS technology.

With some exceptions (e.g., small-diameter post holes, masonry foundations) features should be bisected, and the profile photographed and drawn to scale. If a feature is determined to be a natural disturbance during the excavation process, its excavation may be considered complete after profile documentation. Features should be excavated by stratigraphic zone; if a feature zone is greater than 10 cm thick, it may be appropriate to excavate the zone in arbitrary levels. Each feature zone should be photographed and characterized using USDA soil descriptions and Munsell color codes.

It will often be appropriate to collect soil samples from features for specialized processing and analysis. Consultation with the specialist(s) who will conduct these analyses prior to the initiation of fieldwork activities will ensure appropriate sampling methods are employed. The remaining feature fill should be screened with no greater than 1/8-inch (3.175-mm) hardware mesh; water screening feature fill through 1/16-inch (1.18-mm) window screen is recommended.

Artifacts recovered from features should be kept separate from the general unit artifacts and should be bagged according to the specific context from which they derived within the feature (e.g., which half if bisected, and which stratigraphic zone and/or level if applicable).

Machine-Assisted Excavation

Deep Testing

In certain depositional environments (alluvial, colluvial, and aeolian), deep testing may be an appropriate methodology to identify and uncover buried cultural remains. A geomorphological study should precede and/or accompany any deep testing program.

All trenches should comply with OSHA guidelines for trenching and excavation safety. Trench profiles should be ‘cleaned’ (walls made plumb with shovel and trowel) and inspected for stratigraphy and cultural features. Photographs and a formal profile drawing should be made of at least one wall of each trench. The soil stratigraphy should be documented using USDA soil descriptions and Munsell color codes, and the depth of each stratum should be recorded. All trench locations should be mapped, either with GPS technology or by being tied into an established datum.

Deep testing trench excavations may be done in conjunction with coring and augering, or unit excavation within the trenches. For data recovery projects, mechanical stripping may be used to expose soil horizons with intact cultural features identified by deep testing.

Mechanical Stripping

Mechanically stripping the plow zone or natural overburden in an area may sometimes be an efficient way to expose soil horizons which may contain archaeological features.

An area should first be examined with subsurface investigations such as shovel tests to ensure the presence and depth of the intact cultural deposits. The area that is stripped should be marked on the project map, and preferably mapped with GPS technology.

The machine operator should strip to no closer than 5 cm above the soil horizon of interest, and the remainder of the overburden should be removed by shovel skimming. Exposed features should be treated in a similar manner to those exposed during unit excavation (see Feature Excavation above).

Special Analyses

When appropriate, special analyses should be used to enhance understanding of the archaeological record by answering specific research questions. These analyses include, but are not limited to geomorphological, faunal, shell, pollen, macrobotanical, phytolith, blood residue, and absolute dating. As these analyses produce the best results following specific sampling and processing protocols, consultation with the specialist(s) who will conduct a given analysis should take place prior to the initiation of fieldwork activities. Any expense or time needed for analysis by a specialist should be included in the initial scope of work, and reports should not be submitted until those analyses have been completed.

Artifact Sampling

Sampling strategies may be appropriate on sites with highly redundant quantities of one or more class(es) of material such as brick, shell, or glass. When developing a sampling strategy, the research potential and requirements of potential analytical techniques should be considered to determine sampling parameters for an artifact class.

All sampling decisions and actions should be well documented. At minimum, all materials should be weighed and photographed, and the total weight recorded. The amount of material retained for curation should be discussed with and approved by the OSA review archaeologist prior to implementation, when possible, and the justification for that strategy should be explained in the resulting report. The report and artifact catalog should note the discard of artifacts.

For more information on proper artifact sampling strategies, review the NPS collecting strategy guidelines, which are found in Chapter 5: Curation Prior to the Field and Chapter 6: Curation in the Field and Lab of their Managing Archaeological Collections online publication. Also refer to Discard and Sampling in Part 4.

Hazardous materials such as asbestos, active explosives or armaments, arsenic, radon, or biohazard waste should not be collected for curation. Photography and documentation should be done in the field if it is safe to do so. 

Cemetery Delineation

Cemeteries are protected under North Carolina General Statutes Chapters 14-148 and 14-149 and are afforded consideration under Chapter 65. Cemeteries should be fully delineated through archaeological investigations before any avoidance measures are recommended. If a cemetery buffer is defined without archaeological investigation (GPR or probing) undertaken, then burials may extend beyond the initial proposed buffer. Cemetery delineation should include:

Pedestrian Survey

Bidirectional pedestrian survey at 2 meter transect intervals within an initially proposed 10-meter buffer as defined by initial visual observation and supported by photographs (minimum of 5 transects).

Ground Penetrating Radar

Ground penetrating radar should be done whenever field conditions allow for it. Refer to Ground Penetrating Radar for guidelines on GPR surveys of cemeteries.

Soil Probing and Augering

In cases where GPR surveys are not feasible or impractical (e.g., heavily wooded areas), close interval probing may be used. Soil sampling tubes or augers can also be used and may provide greater information about soil disturbances than probing alone. Recommendations for appropriate methods for probing surveys include:

• Establish site datum and record survey grid boundaries with GPS points.
• Systematic probing transects should be spaced no more than 2-4 feet apart and extend a minimum of 10 meters beyond the last recognizable grave marker or depression.
• Record the locations of any positive probing “hits” and provide a map showing probing transects and the locations of all positive locations.

Protection/Avoidance

Once the cemetery has been delineated, an appropriate buffer should be determined in consultation with the OSA. If the cemetery is on private property, the final buffered cemetery boundary should be mapped by a licensed surveyor, recorded on deeds or plats, and filed with the appropriate county to ensure that the county and any future landowners are aware of its presence. High-visibility construction fencing during construction activities may be recommended near cemeteries that do not have a fence or other physical barrier. If a permanent fence will be added, it should have a gate for accessibility.

While buffer recommendations may vary depending on a variety of factors, the OSA offers the following general guidance:

10-meter (32.8 feet) Buffer

• Modern (mid-20th-century and later) cemeteries.
• Fenced cemeteries unless determined to, or thought to have potential to, be associated with an enslaved community.
• All cemeteries that have been delineated with Ground Penetrating Radar (assuming the GPR survey was done by a professional archaeologist using approved methodologies) or other type of recommended cemetery delineation method where GPR is not feasible (e.g., probing).

15-meter (49.2 feet) Buffer

• Older, post-emancipation family cemeteries.
• Older, post-emancipation community cemeteries.
• Older, pre-emancipation cemeteries that research has shown to have a low potential to be associated with an enslaved community.

30-meter (98.4 feet) Buffer

• Older, pre-emancipation cemeteries determined to, or thought to have potential to, be associated with an enslaved community that have not been delineated with GPR or other recommended cemetery delineation method where GPR is not feasible (e.g., probing).

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Documentation

Field Documentation

The following types of documentation should be used during field investigations: shovel test forms, unit excavation forms, feature forms, field notes, maps, and photography.

At a minimum, the information documented on shovel test forms should include a reference to the project (name or number), date of excavation, excavator(s), shovel test location, soil stratigraphy using USDA soil descriptions, Munsell color codes, depth, and the presence or absence of artifacts.

All maps should include clearly marked reference points that should be established in the field for each site to enable revisits, if warranted. Clearly marked datums should be established in the field for all sites at the Phase II and III levels of effort. These points should be clearly noted on all site maps, and ideally plotted using GPS/GIS data.

Notes should be maintained on photography in the field and should include a reference to the project name or number, the coordinates of the location being photographed, the date the photograph was taken, the photographer, and the subject of the photograph including the cardinal direction of the view depicted.

3D-modeling should be considered as a means of documenting Phase II and III excavations. Structure from motion photogrammetry provides the opportunity to create 3D models of excavation units and features to scale, from which accurate volumes can be calculated. In addition to its analytical utility for standardizing data for comparison within and between sites, 3D models provide a means of documenting archaeological field work activities at high resolution with little additional effort.

Recording a Site

Site locations should be mapped, preferably using GPS technology, and clearly depicted on project maps. Photography should be used to document site conditions, any above-ground features, or other site characteristics deemed important.

In addition, an individual site map should be made that includes the site boundary, project area boundary if it is near or intersecting the site, shovel test locations and corresponding numbers (if not on labeled grid), areas of artifact concentrations, areas of disturbance, structures or other above-ground features, topographical features, and anything else that would assist with site relocation and explaining site formation processes. Any materials not collected should be described in at least general terms with representative photographs and the location included on the site map.

Recording a Site Revisit

When an attempt is made to revisit a previously recorded site, the same procedures described above for recording a site should be used. If the site is not relocated within the previously mapped boundary, a record should still be made, and a site form submitted, demonstrating that there are no longer archaeological remains at that location. This will ensure that no redundant future attempts are made to relocate the site in that area.

When a site is not relocated, a map should be made that includes the originally mapped site boundary, project area boundary if it is near or intersecting the site, and negative shovel test locations and corresponding numbers (if not on labeled grid). Representative photographs of the location should be included. 

Recording a Cemetery

Cemetery locations should be mapped, preferably using GPS technology, and clearly depicted on project maps. Cemeteries containing interments greater than 50 years of age should receive a trinomial site number. Given the possibility for unmarked graves in historic cemeteries, even burial locations with a single above-ground marker should be recorded as cemeteries.

If the cemetery has 10 or fewer interments, then the information available on the grave markers should be documented for all interred individuals. If the cemetery has more than 10 interments, then only the information for the oldest and the most recent interments is necessary, along with a total count of marked burials in the cemetery, and an estimate of unmarked burials (if any are observed). Descriptions may be included of any unusual markers.

Cemeteries are not usually eligible for inclusion in the NRHP unless they possess high artistic value, contain the remains of an important individual for which no other associated property exists, or represent a significant connection to an underrepresented community. National Register Bulletin 41 (Guidelines for Evaluating and Registering Cemeteries and Burial Places) provides guidance on the special criteria for evaluating cemeteries.

GIS Mapping

Use of GIS technologies allows for the creation of more accurately mapped sites and field conditions. The following recommendations apply when using GIS technologies and submitting shapefile information to the OSA:

• An Esri geodatabase or shapefile is preferred, and the recommended projections are NAD 83 NC State Plane (ft) or WGS 1984 Web Mercator.
• Archaeological sites recorded as part of the same project should be grouped together into one polygon shapefile or feature class. Attributes should at a minimum include state site number (if known), temporary site number, and site type (historic/prehistoric/ both). Survey areas should be submitted as a separate shapefile or feature class.

For more complex datasets, please contact the OSA GIS Specialist to devise a data submission plan.

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