PREFACE

In excavating the individual units, the excavator is first concerned with maintaining stratigraphic control;that is, with the removal of a single stratigraphic unit or, if the stratigraphic unit is thick, with the removalof 5–10 cm arbitrary levels within that unit. The plane of these excavations should conform to the dip andstrike of the stratigraphic unit. During excavation, any obvious animal burrows or other areas ofdisturbance should be plotted in plan and profile, and the materials recovered from those areas should bekept separate from the materials recovered from the natural stratum. Any artifacts encountered during theexcavations should be piece-plotted in three dimensions, while materials from the screen areprovenienced to the grid square and stratum or level. If features are encountered during the excavations,then the excavations in that unit should be halted whenever practical, and excavation should shift toadjacent units to fully expose the feature and any activity area surrounding it before the feature itself isexcavated and sampled.Dating is a particular concern with stratified deposits. Ideally, samples for dating should be collectedfrom the base and top of each stratum to date the depositional events in addition to the multiple datescollected from each occupation surface. Samples for radiocarbon dating should be collected away fromany obvious areas of disturbance and preference should be given to charred materials from annuals orshort-lived shrubs to minimize the interpretative problems associated with cross-sectional effect and theold wood problem. With the ready availability of AMS dating, there is rarely a need to rely on samples ofmixed charcoal collected from multiple excavation units within a stratum. Such samples are likely toincluded some displaced materials and at best provide a mean date for the depositional event. Dating ofoccupation surfaces should ideally be based on multiple samples from hearths or other clear culturalcontexts to determine if the occupation represents single or multiple occupational episodes. Althoughradiocarbon dating is likely to be the principal method employed, the opportunity to employ other datingmethods should also be exploited, particularly the more precise methods such as dendrochronological andarchaeomagnetic dating. Direct dating of artifacts or subsistence remains, particularly cultigens, shouldalso receive priority whenever appropriate.Organic preservation at shelter and cave sites generally ranges from good to excellent, so sedimentsshould be sampled liberally to recover archeobotanical and faunal remains. Generally, the entire fill fromthermal features should be bagged for flotation, as should large samples from any refuse deposits. Iforganic materials are well preserved, then samples should also be taken from activity areas associatedwith the occupation surfaces to recover organic materials trampled into the sediments. Coprolites shouldbe collected whenever present. Pollen and phytolith samples should be collected from the same contextsas the flotation samples, and also by column sampling of strata exposed in soil profiles. Any groundstone recovered from the deposits should also be bagged for pollen/phytolith washes. In processingflotation samples, the heavy fraction should be routinely screened through window screen to recoversmall bone fragments and artifacts.Shelter and cave sites are a relatively rare and potentially extremely valuable cultural resource. For thatreason, excavations at these sites should be undertaken with exceptional care and, if preservation andprotection of the site is practical, then a portion of the deposits should be preserved for future research. Inthose cases, the excavator needs to be particularly careful in backfilling the site to avoid damaging theremaining deposits either directly or indirectly by altering the conditions that preserved those deposits inthe first place. The ground surface should be contoured to direct runoff away from the shelter, and geoclothrather than plastic should be used to protect profiles to avoid concentrating soil moisture in theremaining deposits. Excavated areas should be clearly marked so they can be distinguished during futureexcavations, and permanent grid and elevation data should be placed so that provenience controls can bere-established.6-3