General Methods


The following document outlines URS’ plan for the investigation of construction impacts to archaeological resources within the I-95/GIR project area in Philadelphia, Pennsylvania. This plan describes the broad types of archaeological resources/deposits known or likely to exist within the project Area of Potential Effects (APE), the specific methodologies to be employed during the investigation and documentation of these resources, the procedures and studies that will be performed during subsequent laboratory analyses of recovered artifacts assemblages, as well as public outreach activities to be performed in association with the overall Section 106 process.  Throughout these investigations the basic units of archaeological inquiry and resource provenience will be individual historic house lots/properties, as identified in 1950 Sanborn Insurance Maps of the project area.  The following plan anticipates that not all historic properties subjected to archaeological investigation will contain the full suite of resources/deposits outlined below.

Archaeological investigations within the I-95/GIR project area will involve a three-pronged approach that incorporates and integrates archival and historical background research, controlled excavation and archaeological documentation, and laboratory analyses of recovered artifact assemblages. All activities and studies completed in conjunction with these investigations will comply fully with the requirements of the Pennsylvania Historical and Museum Commission’s (PHMC)Guidelines for Archaeological Investigations in Pennsylvania 1.  In addition to the general approaches outlined below, site-specific data recovery methodologies and research designs will be developed for each historic property requiring Phase III mitigation investigations.  These data recovery plans will be submitted to both the Pennsylvania Department of Transportation (PennDOT) and the Pennsylvania Historical and Museum Commission (PHMC) for review and concurrence prior to the start of mitigation efforts.

Historic Background Research

Intensive background and archival research will be conducted concurrent with fieldwork, and will seek to collect additional and more detailed information about the historic development, use, and occupation of the property over time, as well as that related to the development of the surrounding community. Background research will also encompass the Native American site component and will involve the gathering of comparative data from the Pennsylvania Archaeological Site Survey (P.A.S.S.) files pertaining to comparably aged sites previously identified in Philadelphia and the surrounding region.

With respect to the historic component, AECOM researchers will utilize online resources and visit relevant local archival repositories, including the Pennsylvania Historical Society, the Philadelphia City Archives, and the Free Library of Philadelphia, in order to search for primary and secondary resources (deeds, surveys, maps, photographs, published histories, etc.) related to the project area as a whole.  Specific background research will seek to establish complete occupational histories for historic properties subjected to Data Recovery documentation, and to collect information related to the individual households who occupied these sites over time. Data relating to past land-use patterns and occupants will be critical to the final interpretation of archaeological materials recovered from the project area. AECOM staff has established contact with local historians and descendants of project area residents so that they can collaborate with any information they may possess relative to the development and history of the project area, and researchers will continue to work closely with these individuals throughout the course of the investigations. Historic maps collected during background research will be georeferenced within the larger project area map.

Controlled Field Investigations

Cultural Resource Potential

Based on the findings of prior Phase I investigations it has been determined that the project area exhibits an overall high degree of archaeological resource preservation.  Moreover, the project area is likely to contain a wide variety of specific resource types, including those associated with both prehistoric/Native American and historic periods of occupation.  A categorized list of anticipated resource types is summarized below.

Historic Ground Surfaces

Historic ground surfaces are represented by intact or partially impacted naturally occurring soil horizons that contain deposits of in situ prehistoric/Native American and/or historic era artifact deposits. Individual soil strata that fall within this category include those identified as A, E, and B horizons, and that either represent the present day ground surface or are sealed beneath fill deposits of variable depth and thickness. In addition, other deposits that may qualify as historic ground surfaces include secondary A/Ap horizons formed within fill deposits and artificial fill deposits utilized at times in the past as living surfaces.  Artifacts contained within these soil horizons will take the form of sheet midden deposits that can provide significant information related to site chronology, the presence, distribution, and organization of functionally discreet activity areas, and the use of space within a given prehistoric occupation or historic lot.

Near-Surface Features

Near-surface cultural features may be either prehistoric or historic in age and cultural affiliation, and encompass all manner of intrusive excavations contained within, or immediately below, historic ground surface soil horizons.  Within the context of this data recovery plan, such features will be defined as exhibiting a final depth less than four (4.0) feet below the present ground surface.  Examples of near-surface features include post-holes, lined and un-lined pits, “barrel privies”, hearths, drains and utility trenches, and both human and animal burials.  Shallow features such as these can provide information related to the use of space, the presence and location of prior structures and landscape elements, and the nature of refuse disposal within a given site.  Artifact deposits contained within or found in association with these types of features can be informative about a range of domestic, socio-economic, and health issues associated with past occupants of a given site.

Deep Features

As defined for the purposes of this plan, deep cultural features will likely be exclusively historic in age and consist of intrusive excavations that extend to depths of more than four feet below the present ground surface.  Features falling into this category are anticipated to be limited to a relatively limited variety of forms, including large “barrel privies” (consisting of two or more vertically stacked barrels, or in some cases square boxes) and brick-lined shaft features (wells, cisterns, privies).  Phase II testing of the project area has already demonstrated that wood-lined barrel/box privies can extend to depths of between six and eight (6-8) feet below ground surface; while brick-lined shafts could reach depths of 15-25 feet below ground.  Unlike the first two resource categories above, excavation of deep features will require the use of OSHA compliant shoring systems to allow for safe access to artifact deposits by members of the archaeological team.

Historic Structural Remains

Historic structural remains consist of the intact or truncated remnants of former residential, commercial, and industrial buildings, including foundation walls, basement floors, pier footings and related elements.

Under this plan these structural remains will not be normally considered to represent potentially significant resources in their own right. However, given that such features can provide critical information related to historic property identification, the allocation and use of space within specific lots, the functional and chronological interpretation of associated features, changing land use patterns, and overall site developmental sequences, all exposed structural remnants will be thoroughly mapped, documented on standardized forms, identified with respect to buildings exhibited in historic maps of the project area and surrounding vicinity, and photographed.  In addition, all identified foundations will be assigned sequential Structure Numbers within each archaeological segment of the project area, and will be linked wherever possible to specific street addresses.

It is understood that, in many cases, historic foundation remains and associated cellar holes will not be able to be fully excavated and documented. However, in instances where such investigations can be performed safely a sample of historic foundations will be excavated to the extent possible and recorded.  Likewise, for any structures not depicted in historic maps of the project area, and that could be associated with early settlement and development in Philadelphia, all reasonable efforts will be made to excavate and document those physical remains as completely as possible.  Decisions regarding the selection of historic structures for more complete investigation will be made on a case by case basis by the project Principal Investigators in consultation with PADOT and PHMC archaeologists.

Field Methodologies

The primary goal of controlled field investigations will be to recover a representative / comparative sample of artifacts from a given historical lot (including artifacts that can be used to more precisely date identified cultural deposits), to expose any intact features that may be present, and to document, recover, analyze, and interpret intact artifact deposits contained within site deposits and features.

Historic Ground Surfaces

Intact historical ground surfaces and soil horizons selected for data recovery investigations will be mitigated through the completion of a series of 3.0 X 3.0-foot or 5.0 X 5.0-foot square excavation units (EUs). All EUs will be excavated by discreet natural strata and in arbitrary 4-inch (ca. 10cm) levels within undisturbed soil horizons. Excavations will proceed to a depth at least 4 inches (10 cm) into sterile subsoil deposits.  One hundred percent (100%) of all excavated soil will be screened through standard ¼-inch hardware cloth, and all recovered artifacts will be assigned a sequential Field Sample number (FS#) linked to the precise location and stratigraphic context of those materials, afforded any appropriate temporary conservation and/or stabilization procedures that may be required, and retained in plastic bags labeled with all appropriate vertical and horizontal provenience information.  Records of the unit excavations, including the Munsell color, texture, and depth of all soil horizons, along with the artifact content of each stratum, will be recorded on standardized paper forms and maintained with the project files. Exposed soil profiles will be recorded via hand-drawn maps and both high-resolution digital and archival black and white photographs. Soil samples will be retained for further study where appropriate. The number and distribution of EUs necessary to effectively mitigate construction impacts will be worked out in advance of fieldwork and in consultation with PADOT and PHMC archaeologists.

Near-Surface Features

Near-surface features identified within the I-95 project area will be excavated by hand and initially bisected in order to reveal and document internal fill structure and stratigraphy.  If bisection reveals the presence of no potentially significant artifact deposits, then archaeological documentation will terminate once this process has been completed.  If potentially significant artifact deposits are identified, then full excavation (mitigation) of the feature will be undertaken.  Full excavation of select features may also be executed if they are found to be unique in form and/or function, and in order to fully record the associated physical attributes of such examples.

During all excavations, feature fill will be removed by observed internal strata; however, in some instances smaller arbitrary divisions may be maintained within primary cultural deposits where such deposits exceed one foot in depth and where the use of such finer divisions is likely to yield analytically significant data. One hundred percent (100%) of all excavated matrices will be dry-screened on site through ¼-inch hardware cloth. Standardized paper field forms will be used to record data relating to the depths, Munsell color and texture, and artifact content for each shaft fill stratum. Feature depositional profiles will be fully recorded by means of hand-drawn maps and by fine-grained black/white and high-resolution digital photographs.

Constant-volume soil samples will be collected from all artifact-bearing primary deposits within features and retained for flotation and/or future specialized studies. Soil samples will not exceed 1.5 liters in size.  One liter (1.0) of each sample (ca. 67%) will be specifically set aside for flotation processing at the conclusion of fieldwork, while the remaining portions will be retained for possible future specialized studies.

Deep Features

Deep cultural features found to contain intact artifact-bearing primary deposits, and selected for data recovery investigations, will be excavated in a manner not unlike that discussed above.  Intact deposits will be bisected and excavated by observed fill horizons.  One hundred percent (100%) of all excavated intact primary fill deposits will be screened through ¼-inch hardware cloth.  Approximately 25% of all secondary fill deposits (ash/cinder, construction/demolition rubble, and related fills) will be screened for artifact content; any observed temporally diagnostic artifacts within such fills will be retained for further analysis.  Deep feature documentation will follow the procedures and methods outlined above.

For safety reasons, excavation of deep artifact bearing deposits (> 4.0 feet deep) will be completed in vertical sections not to exceed four (4.0) feet in total depth, with data on internal stratigraphy progressively added to the feature profile. Constant-volume soil samples as described above will be collected from all artifact-bearing primary deposits within features and retained for flotation and/or future specialized studies. All other procedures to be followed during the mitigation of deep features will be the same as those outlined in the section above.

Geomorphological Studies

Geomorphologic examinations of the intact soil profiles within the I-95 study area will be performed by Dr. Dan Wagner of Geo-Sci Consultants.  The purpose of these studies will be to characterize the development of preserved undisturbed soil horizons and to formulate interpretations regarding the age and nature of landform evolution within examined areas, to assess issues pertaining to landform stability over time, and to document the nature and extent of impacts to the local landscape during the historic era.  Information generated by these studies will assist not only in the interpretation of any associated archaeological deposits, but will also provide critical baseline data that can be used by future archaeologists to evaluate the cultural resource potential of this section of Northeast Philadelphia.  The findings of all data recovery related geomorphologic investigations will be fully documented in a separate report that will be included as an appendix in associated Phase III reports of findings.

Site Mapping

All archaeological testing and identified cultural resources will be intensively mapped using a combination of sub-meter accurate Geographic Information Systems (GIS) data collection and Total Station survey equipment.  GIS data will be used specifically to tie archaeological findings into the larger project area map, while Total Station tools will be used to establish specific testing grids, to identify individuals test locations, and to establish spatial relationships among and between archaeological resources.

Laboratory Investigations

Artifacts excavated during this investigation will be processed and inventoried at URS laboratory facilities in Burlington, New Jersey.  All artifacts and samples recovered from the I-95 study area will be fully processed, analyzed, conserved, and curated in accordance with the PHMC Curation Guidelines 2.  Processing of recovered materials will be conducted by URS laboratory staff and will include the specific tasks outlined and discussed in greater detail below.

Artifact Processing

All artifacts and samples recovered from the I-95 project area will undergo standard processing in preparation for their subsequent analysis and interpretation. During this stage of work artifacts will be washed with soft-bristle brushes using water mixed with Orvus (a neutral pH synthetic anionic detergent) and will be air-dried on racks. Artifacts with fragile surfaces (such as tin-glazed ceramics or porcelains with over-glaze decorations) will be washed separately. Objects requiring special stabilization will be separated from the larger collection at this time and prepared for their specified treatments.

Once artifacts have been allowed to thoroughly dry, artifacts from each depositional context will be sorted by gross raw material category (e.g., ceramic, glass, metal, etc.). Artifacts will be labeled with assigned catalog numbers using archival ink. After artifacts are labeled and sorted by gross type, they will be placed in various sized 4-mil polyethylene bags labeled on the outside with appropriate provenience information using permanent markers.

Computerization of Artifact Data

To facilitate information collection, record a high level of detail, and to allow complex relational analyses of artifact data, URS utilizes a centralized but unconstrained three-tiered artifact data management and analytic system.  Through the creation of databases with free-flowing structures, URS is able to maximize computable information while minimizing data-entry time. This three-tiered system allows for the recording of artifacts in increasing levels of detail, dependant on the quality of the artifact’s archaeological context.  The first tier of analysis records the provenience, count, type, and form of artifacts.  The second tier of analysis involves spatial and qualitative artifact patterning.  The third tier of analysis concerns specialized studies of artifacts from site contexts with good integrity.  Such specialized studies include, but are not limited to, frequency analyses, minimum vessel counts for ceramic and glass artifacts, and vessel reconstruction.

Artifact Conservation

Concurrent with artifact processing and analyses, materials recovered from the site will be examined by URS laboratory personnel for the purpose of identifying any specific objects or groups of objects that may require immediate stabilization through conservation measures.  Any required stabilization measures will be initiated in a timely manner to ensure that significant artifact degradation does not occur. Assessment and conservation of artifacts will be an ongoing laboratory process throughout the project. Passive conservation measures, such as the use of proper storage bags and archival materials, will be applied to the entire collection.

Artifact Analyses

Native American / Prehistoric Materials

Given the limited size of preserved backyard space within this site, and the extent to which historic ground surfaces have been punctuated by pit features, it is anticipated that Native American artifact deposits will not provide a great deal of significant information related to the nature of prehistoric occupation at this location. However, given the dearth of recorded Native American sites in Philadelphia, any baseline data that can be recovered regarding site chronology, lithic exploitation, site function/activities, etc. will be extremely useful for comparison with other known prehistoric occupations in this vicinity.  In addition, any data that can be used to more fully interpret this occupation will be of great utility in terms of formulating/improving predictive models of Native American site location and preservation in adjacent sections of the city.

All Native American artifacts will be analyzed with respect to raw material type and will be classified using standard procedures for identifying specific tool forms (e.g., projectile points, bifaces, cores, scrapers, etc.).  The dimensions of all lithic tools will be measured in millimeters and weighed in grams. Significant or diagnostic tools will also be photographed or illustrated for the final report. Designations of age and cultural affiliation will be made for diagnostic artifacts, based on commonly accepted and employed regional morphological typologies.

Lithic debitage will be analyzed in terms of amount of cortex, size categories, and raw material, thereby allowing for a correlation of stages of manufacture/reduction sequence.  Debitage will also be examined for evidence of retouch or use-wear. All identified tools will be examined via low-power (10X – 60X) microscopy in order to identify and characterize any edge polish, striations, and/or micro-flaking present.  Such evidence will, in turn, be used to infer tool function and the nature of use.  The location, nature, and extent of all use wear will be documented both in the database and via high-resolution digital photography.  Fire-cracked rock will be separated by material type, then counted and weighed by provenience.  If appropriate, attempts will be made to cross-mend any identified clusters of fire-cracked rock to link deposits and features across the site.

Prehistoric pottery will be documented on the basis of temper, surface treatment, rim forms, and (where possible) vessel size. All pottery will be classified using standard regional typologies. As with lithics, analyses of pottery vessels will assist in identifying activities that occurred at each site (e.g., cooking and storage).  Further, it may be possible to use decorative motifs for intra- and inter-site analysis to determine if sites in the same general area were occupied by “related” social groups.  Significant examples of pottery will be photographed or illustrated.

Historic Era Materials

At a minimum, basic analyses performed on recovered historic artifacts will include the identification of key characteristics for each object, including general form and function (e.g., cut nail – architectural), material composition (ceramic, glass, metal, etc.), ware type (creamware, lead glass, white ball clay, etc.) manufacturing technique, decoration, date of manufacture, and maker’s marks (if present), following accepted standards delineated in Hume 3, South 4, and Miller et al. 5, among others.  Dated artifacts will be utilized to establish terminus post quem (TPQ), terminus ante quem (TAQ), and mean dates for specified intact archeological deposits Artifacts recovered from intact and/or primary deposits will additionally undergo more intensive analyses designed to facilitate the interpretation of these materials and the context in which they were found, as well as to help answer the research questions developed for this project.  In particular, glass and ceramic artifacts will be cross-mended both within and between appropriate depositional contexts and the mending information used to calculate the minimum number of vessels present (MNV). Additional artifact characteristics will be recorded for identified vessels, including that related to details of decoration, use-wear, specific functions, and, for bottles, any information about their contents.  Comparative statistical data will be generated for artifacts recovered from each identified depositional/study unit within discreet features.

Faunal Remains

Teagan Schweitzer will perform the identification, quantification, and analysis of faunal artifacts at her laboratory facilities at the University of Pennsylvania. Basic faunal data collection activities will involve the identification of all sample specimens as to species when possible, and by class and size range in the case of fragmentary or indistinct remains.  Faunal remains will further be identified as to represented body part and age at death and will be inspected for signs of cut marks and other evidence of butchery or additional secondary bone modification. From this basic information the faunal analyst will complete statistical studies regarding faunal representation by species and body part and will also provide estimates by provenience regarding the minimum number of individuals (MNI) of each species present.  From this quantified data interpretations regarding the diet and health of site occupants will be formulated. Data collected from this faunal assemblage will be compared and contrasted with materials recovered from comparably dated sites from other sections of Philadelphia in order to identify potential differing or unique foodways/consumption patterns.

Macrobotanical Remains

Macro-botanical (floral) materials will be analyzed by Dr. Heather Trigg of the Fiske Center for Archaeological Research at the University of Massachusetts in Boston.  Floral remains may be used to address a similar range of research issues as faunal remains, including the examination of health and dietary characteristics, and the identification of patterns of plant food consumption that may be indicative of household income and/or dietary preferences.  Botanical materials recovered from soil floatation samples will be sorted according to taxonomic categories (e.g., wood, seed, nut shell) and quantified by weight and fragment count.  Specimens will be analyzed under low magnification (10X-40X) and identified as to species, genus, or family, depending on the degree of preservation and representation.  Analytical findings will be tabulated in an electronic statistical database and used to address issues relating to diet, health, and food preference habits.

Soil Flotation

Soil samples collected in the field will be processed through standard flotation equipment to facilitate the recovery of both floral and faunal samples, as well as other residual artifact samples contained within the soil matrix. It is anticipated that this process will be completed at the URS laboratory facilities in Burlington, New Jersey. Where sufficient samples have been collected, a standard quantity of 1.0 liters of soil will be processed through flotation equipment. Artifacts recovered from each sample context will be subsequently sorted by type, placed in plastic bags labeled with all appropriate provenience and other identifying information, and prepared for subsequent specialized studies or other analyses.A minimum of 0.5 liters of soil from each context will be retained for possible future analyses.

Soils Analyses

The analysis of phytolith, pollen, and parasites contained in recovered soil samples will be performed by Linda Scott Cummings of the PaleoResearch Institute (PRI). For soil samples derived from privies, the analysis of these biological remnants can generate significant data regarding health, sanitation, and medical care in the eighteenth and nineteenth centuries, including aspects of diet and commonly suffered gastro-intestinal ailments. In the event that any intact ground surfaces are identified within the site, these studies can provide exceptional information that can be used in delineating and interpreting the use of space within backyard areas, including the identification of possible functionally specific activity areas.

Carbon-14 Dating

Should Data Recovery excavations result in the identification and mitigation of any Native American features from which carbonized wood samples can be recovered, a sample of this material will be submitted for C-14 dating.  One sample from each feature level containing such material will be selected for analysis.

Photo-documentation of the Artifact Assemblage

Selected diagnostic artifacts will be photo-documented during the analytic process. Photographs will be taken primarily for two reasons: 1) to use in reports, exhibitions, brochures, professional presentations, and other public outreach projects and 2) to provide a visual record of some of the artifacts. The photographs will be primarily high-resolution digital color images, with some black and white prints taken as needed for recordation purposes. The artifacts chosen for photography will be from significant contexts or will be noteworthy as examples of particular classes of material, styles, or manufacturing techniques.

Permanent Curation of the Collection

All artifacts will be packed for permanent curation following the PHMC Curation Guidelines 6. Artifacts will be packed using only acid-free, durable materials. The Pennsylvania State Museum will receive all project related products, including the artifact collection, final report, and additional project documents including field notes, field records, maps, and photographs. The collection will be hand delivered to the State Museum of Pennsylvania, per their guidelines.

Select collections or assemblages of recovered artifacts may be set aside and separately curated for eventual long-term display/exhibit at one or more cultural repositories in Philadelphia.  The development of any such select exhibits will be coordinated with project officials and the staff of the Pennsylvania State Museum, and prepared in accordance with current Museum guidelines.

Project Coordination and Meetings

Meetings between URS, PADOT, and PA SHPO will be scheduled as needed during the conduct of Phase II testing and Phase III data-recovery investigations, and will serve to discuss project progress and strategy toward concluding the project’s Section 106 responsibilities pertaining to archaeological resources.


  1. Pennsylvania Historical and Museum Commission (2008). Guidelines for Archaeological Investigations in Pennsylvania
  2. Pennsylvania Historical and Museum Commission (2006). Curation Guidelines: Preparing Archaeological Collections for Submission to the State Museum of Pennsylvania
  3. Noël Hume (1970). A Guide to Artifacts of Colonial America
  4. South and South (1977). Method and Theory in Historical Archeology
  5. Miller, Samford, Shlasko and Madsen (2013). Telling Time for Archaeologists
  6. Pennsylvania Historical and Museum Commission (2006). Curation Guidelines: Preparing Archaeological Collections for Submission to the State Museum of Pennsylvania