Mississippi Administrative Code
Title 16 - History, Humanities and Arts
Part 3 - Historic Preservation Division
Chapter 12 - Mississippi Standards and Guidelines for Archaeological Investigations
Rule 16-3-12.6.3 - Archaeological Survey and Methodology

Visual Inspection/ Visual Pedestrian Survey

When field conditions warrant, systematic visual inspection of plowed fields and surface collection of artifacts has proven to be a highly effective and efficient method of site survey. Systematic surface collection is encouraged after re-plowing and disking of previously plowed fields to a depth no greater than the previous disturbance prior to inspection. However, even in previously plowed areas, the clearing of trees and large brush to facilitate surface collection has the strong potential to disturb sub-plowzone soils and, therefore, is not regarded as an acceptable methodology. All exposed surfaces are to be inspected. If an area has greater than 50¢ surface visibility but is in a dynamic depositional environment (e.g., the foot of a slope or adjacent to an aggrading waterway) or the scope of work includes substantial/significant sub-plowzone disturbance, then 30-m (~100-ft.) interval subsurface testing is required.

Highly eroded areas, where subsoil is visible at or just below the surface, as well as recently plowed fields are the most common instances where such high visibility exists. The archaeologists' judgment concerning visibility is especially critical in fallow or dry fields, where close-interval (30 m) subsurface testing will be necessary. In general, pedestrian survey will be systematic in coverage, with the maximum interval between surveyors not exceeding 30 m.

Surface visibility and topography alone do not sufficiently define a site. When an archaeological site is identified by visual inspection alone, excavation of at least two shovel test pits (STPs) is needed to assess site depth and the presence or absence of intact cultural strata and/or feature, and assist in boundary delineation. However, low probability areas (for example, poorly drained soils and steep slopes, generally with a grade greater than 15%) and extensively disturbed (for example, previously subjected to land-leveling, clearing and grubbing activities, and other similar earthmoving activities) non-floodplain areas need only be subjected to visual inspection. If the visual survey locates natural benches, quarries, or other cultural features, the visual testing is to be augmented with additional, selectively or judgmentally placed, STPs.

Surface Collection

At the survey level, a complete surface artifact collection should not normally be made unless the site contains few artifacts or shows evidence of previous and/or active looting or vandalism. If a surface collection is made, an appropriate sampling method should be utilized and based on the investigator's assessment of field conditions as well as the type and density of artifacts present. An investigator's collection strategy should be specified in field notes, for example: all diagnostics and a representative sample of other observable materials, or controlled and repeatable samples of every surface artifact in designated locations, or a minimum number of each type of historic ceramic and glass plus other diagnostic items, etc. Surface collection is not a valid survey strategy on sites where ground visibility is less than 50%.

Surface visibility and topography alone do not sufficiently define a site. Although a surface collection may help to define horizontal site limits, it should be supplemented with more traditional subsurface testing, particularly when surface visibility is discontinuous or variable. Subsurface testing also provides information about stratigraphy, the vertical distribution of material, and site integrity which cannot be obtained from pedestrian survey data alone.

Subsurface Survey

Although a surface collection may help to define horizontal site limits, it must be supplemented with subsurface testing, particularly when surface visibility is discontinuous or variable. Subsurface testing also provides information about stratigraphy, the vertical distribution of material, and site integrity, which cannot be obtained from visual survey alone and is necessary to establish the extent of a site even when surface visibility is unrestricted, and topographic changes indicate a possible boundary. Excavation of STPs (Shovel Test Pits, square in profile and not smaller than 12 inches [30 cm] in width) remains one of the most reliable means of site identification in areas of low surface visibility. Whenever possible, STPs are to be tied to a known datum or fixed reference point, with their location clearly marked on appropriate maps.

As a general rule, STPs are to be excavated at intervals no greater than 30 m and will continue to culturally sterile subsoil, if possible. Thirty-meter interval shovel tests can be used to establish the general boundaries, with two consecutive negative shovel tests establishing the edge of the site. Thus, the interval between two distinct sites will be at least 60 m (197 ft.).

Different site types, as well as soils and topography, may justify differing STP intervals. A shorter/tighter interval is recommended if small, low-density sites are encountered. Shorter intervals may be utilized after consultation with and approval from MDAH archaeology staff. The standard 30-m interval for STPs may also be augmented by judgmental testing in high probability areas such as promising landforms or areas containing vegetation or cultural landscape features associated with known or suspected sites locations.

Archaeological site boundaries are to be established by excavating radial shovel tests in no less than four directions. When these resources are identified, it is recommended that the consultant implement a close-interval (5-10 m [16-33 ft.]) shovel-testing strategy to delineate both the horizontal and vertical boundaries of the resources within the survey area. Close interval shovel testing should be continued within the survey area until two sequential negative tests are completed. This may be achieved through the use of a cruciform delineation (i.e. in all four directions from a site datum) or grid strategy as long as the spacing of between 5 and 10 m is maintained to establish site boundaries. Additionally, 5-10 m intervals should be excavated to determine whether individual artifacts recovered from lone or single STPs with no adjacent positive STPs represent isolated finds or small low-density sites.

All soils from STPs must be screened through --inch hardware cloth. All artifacts fifty years of age and over are to be retained with the exception of materials such as brick, shell, charcoal, etc., which may be quantified in the field, a sample retained, and the remainder discarded. Shovel tests are to be excavated to a depth of at least 70 to 80 cmbs (centimeters below surface) (2.3 to 2.6 ft.) or until impenetrable substrate (i.e., bedrock or clay), known culturally sterile subsoil, or the water table is reached (see 6.4. Special Environment Surveys ). If excavation exceeds this depth, an auger or Oakfield soil probe should be employed from the base of shovel test excavation to a maximum depth of 120 cmbs (3.94 ft.).

Notes on all STPs and trenches will be recorded and are to include information on survey/site/transect identification and location, with a representative profile drawing or detailed description of strata, soil types, Munsell descriptions, depth measurements, and a listing of artifacts (both kept and discarded). Note the environmental conditions under which any testing strategy was employed (for example, adverse weather, condition of ground surface, etc.). A detailed map is to be prepared showing areas surveyed, areas eliminated from survey due to disturbance, slope, wetness, etc., and the location of the positive and negative STPs.

Remote Sensing

Remote sensing should be used to augment more traditional survey methods by identifying high potential areas for subsurface testing. Remote sensing (using metal detectors, proton magnetometers, ground penetrating radar, etc.) is recommended for sites associated with the Contact Period or Civil War, and is particularly useful for identifying burials. In underwater survey, remote sensing is often effective in identifying targets for later diver verification. A specific case is to be made in the research design for the use of remote sensing and its relationship to other survey methods made explicit.

Four geophysical techniques are principally employed in archaeology: magnetometry, electrical resistivity, electromagnetic conductivity (EM), and ground-penetrating radar (GPR). For a discussion of each approach, their suitability in various environments, and the latest advances in the field of geophysical methods (see Geophysical Surveys as Landscape Archaeology by Kenneth L. Kvamme).