Discovering Prehistoric Sites:
Objective and Subjective Survey Techniques
by:
Daniel G. Foster, Brian D. Dillon, and Linda C. Sandelin
California Department of Forestry and Fire Protection (CDF)
Revised date: June 13, 2005
Gallery of PHOTOS
Introduction
This paper contains numerous suggestions and methods designed to improve the effectiveness of archaeological surveys supporting CDF projects. Such surveys must be conducted to identify all classes of cultural resources including archaeological sites, historic sites, cultural landscapes, and traditional cultural properties. The main focus of this paper, however, is to provide suggestions, techniques, and strategies to maximize the reliability and success of survey work leading to the discovery of previously unrecorded prehistoric archaeological sites. We want to clarify that survey work must also include an intensive search for all types of cultural resources as well as prehistoric sites, but some of the other types of cultural resources do not typically exhibit the same kind of location patterning discussed here and should be treated separately. Traditional cultural properties, for example, which include plant collecting localities, sacred sites, and ceremonial locations and may not exhibit artifacts or other physical evidence of traditional use, are types of cultural resources that must be inventoried with different techniques. The best method to search for the possible existence of such resources is consultation with the local Native American groups. Without completing that step during cultural resource inventory work, these resources are not likely to be identified, or their significance fully appreciated, as places of cultural or religious importance. While some historic landscapes, sites, and features are readily apparent to an observant field surveyor, some of these resources can easily be overlooked as well. It is important for the surveyor to have completed adequate prefield research to understand the history of land use and be ready to locate and recognize features or alterations to the landscape related to historic use. These survey procedures must be employed in addition to the techniques discussed here for prehistoric sites and features.
This paper emphasizes the merits of predictive modeling as a means to identify areas likely to contain prehistoric archaeological sites. Most prehistoric sites and some historic sites do occur in predictable locations. These likely areas should be identified prior to the survey, mapped, and be subjected to intensive archaeological survey. Keep in mind, however that several types of cultural resources can be found in unpredictable locations so be alert at all times during your survey and fieldwork for the project. The techniques discussed here are organized into three categories: how to look, where to look, and what to look for.
Pre-Field Research
The investigator should always conduct a records search with the appropriate Information Center of the California Archaeological Inventory to determine if any known sites exist or if the area has received previous archaeological study. The Information Center may also provide information concerning the sensitivity of the project area, if so requested. The record search must be current (conducted within the past five years). This search will only show those sites previously recorded within your survey area. There may be additional unrecorded sites on the property that you will need to find through archaeological survey.
The surveyor should become acquainted with archaeological, ethnographic, and historical literature pertinent to the region as these are valuable sources of information. You may wish to contact your local US Forest Service archaeologist or CDF archaeologist for advice on what types of sites are found in a given area, archaeological sensitivity determinations, and listings of available cultural resource references.
The investigator should also consult with representatives of local Native American communities prior to the survey, to seek information they may have concerning the possible presence of archaeological or spiritual sites within or near the area. This contact is now required by the Forest Practice Rules for THPs, and by CDF policy for most other types of CDF projects.
You should always ask the landowner, ranch foreman, property manager, or any other knowledgeable individuals if any artifacts or sites have been found on the property. Ironically, this is probably the easiest and quickest technique of all, yet it is often the most valuable method to identify archaeological sites within a CDF project area and must never be omitted. Oftentimes landowners are willing to show an archaeological surveyor where artifacts were collected from the property.
Topographic Map Review: Always carefully examine the project area on an original USGS 7.5' quadrangle to evaluate archaeological sensitivity and plan an appropriate survey strategy. Archaeological sites within California's forest and range wildlands usually occur in three main topographic settings: stream terraces, mid-slope benches, and ridgetops. Flat areas along streams are excellent locations for prehistoric and historic sites. Any such areas should be identified during topographic map review and highlighted for careful archaeological survey.
Prehistoric sites often occur near the location where two streams come together, unless the stream occurs in a steep canyon without benches. Pay particular attention to the point of land above (immediately upstream from) the confluence. All ridge tops should be surveyed, but give extra attention to trending ridges. Prehistoric people used these as travel routes through the mountains.
Highlight any mapped or known springs occurring near ridgetops or ridgetop saddles for careful inspection. A ridgetop saddle is a low, flat area situated between two points of higher ground. There are two principal reasons why prehistoric people chose to camp at ridgetop saddle locations. They provide shelter from wind and also, ridgetop water sources and accompanying vegetation often occur in association to saddles rather than ridgetop peaks.
Original quad maps can show natural openings in the forest which do not appear on photocopies. This is why you should always study the project area on a real quad. Also be alert for place-names such as "Indian Bar", "Arrowmakers Ridge", "Site", etc.
Historic mines and ranches are sometimes shown on quad maps and may indicate potential archaeological resources. These places may be historic homesteads with significant historic features nearby, and also are camping places often chosen by Native Americans as the best flat area and near the most reliable water source. The margins of interior valleys are particularly sensitive since major prehistoric villages were often established within them. Quad maps also show rancheria boundaries, cemeteries, and possible historic structures as hollow squares. After carefully reviewing the USGS topographic map, the surveyor should identify all likely areas and conduct intensive surveys at these locations.
Air Photos and GLO Maps: Another useful technique for discovering archaeological sites is careful examination of the project area on aerial photographs during your pre-field research. Sometimes meadows and forest openings not shown on quad maps are depicted. The most useful source of cartographic information for pre-field research in historic contexts are the old Government Land Office (GLO) maps, which can date as early as the 1850Õs in California and which show every possible kind of historic feature, from mule-paths to fencelines to minerÕs cabins, all with the names of the owners or builders prominently displayed. Old mining ditches, flumes, or rock walls are sometimes identified even to the names of the stockholders in the companies which paid for them, mining claims are named and numbered, and even the ethnic affiliation (Chinese, Sonoran, Chilean, etc.) of the miners living within a given camp or even structure are often given. In some cases, prehistoric archaeological information is provided (abandoned Indian village, Indian footpath, Indian ford at river, burial ground, etc.) on these historic maps as well. The GLO maps for any given area may also have been updated every couple of years, so try to get all editions if you can- - you will often be able to tell not only when a given historic road, railroad grade, or mining camp was built, but also when it was abandoned from the different map editions.
Old-TimerÕs Interviews: Be sure to talk to any and all old-timers you may know of before you go into the field. These can be elderly Indians, old loggers or sawmill hands, hunters, trappers, ranchers, rangers or even bootleggers. Remember, regardless of how little you may know about the prehistory, ethnology, or early history of any given area, there always is someone out there just brimming full of knowledge and itching to share it with you. These interviews can be done over the telephone, but are much more effective if done in person. In person, you can spread out your maps and have the old timer get as specific as he or she can about your area of interest. You can also ask about historical photographs, maps, etc. that your informant may have in his or her possession. Of particular interest is seeing if your informant can identify placenames on your maps with people or events that only they may know about now- - in particular, elderly Indian informants typically have a wealth of information about places on maps that today are now completely without names- - - try to get the Indian names for these localities, and the English or Spanish translations for them whenever possible.
Historical societies are the best possible source of information about early historic events and personalities in backwoods California. And, the most informative old-timers in your area may already be members of the local county historical society or a close friend of one of the members.
How to Look
The first and possibly the most important technique to emphasize is how to go about searching for prehistoric archaeological resources during surveys of CDF projects. It is extremely important to carefully inspect the ground surface as you walk through the project area. This may require periodic clearing of vegetation, leaf litter, grass, or anything that obscures visibility of mineral soil. The correct body position when walking archaeological survey transects is one slightly bent-over to focus inspection upon the ground. And, donÕt just stand up, get down on your knees from time to time, pick up that rock or pebble, feel that soil, and brush off that rock surface. At the end of a long day of archaeological surveying, your body should be as tired as if you had gone rock-climbing or spent the day picking tomatoes: if it is not, you are not Òassuming the positionÓ correctly in looking for surface artifacts.
If systematic survey coverage is being employed (such as straight-line or on-contour transects with a measured transect interval) be sure to stop transect coverage when a likely or suspicious area is encountered. This area should be intensively searched before transect survey is resumed. In other words, donÕt let the ÒrulesÓ get in the way of the discoveries. One common mistake we see is surveyors being too careful to stay on systematic transect patterns and walking right by area that should have been searched more carefully. Stop and go inspect that rock outcrop and surrounding areas, then go back to the transect line to resume coverage. Sometimes surveyors assume they can pick it up on the return transect. It is far better to stop and search immediately when likely areas are first encountered. Remember, the objective is to discover resources that may be present out there, transect survey coverage is simply a tool to ensure the entire project area gets covered. Many surveyors will be CDF Foresters, Firefighters, and private sector personnel that may be completing other duties in addition to archaeological survey while conducting fieldwork. It is acceptable to conduct other tasks while out in the woods, but be sure to proceed slowly enough so adequate time is provided for reliable archaeological survey work. Do not attempt to conduct archaeological survey work when conditions obscure visibility. Survey work should be only conducted in good weather. Our experience has shown that survey work conducted during heavy windstorms, or when rain, or snow are falling (even gently), are not reliable. Do something else that day and come back for archaeological survey when conditions improve.
Be sure to walk and carefully survey along all roads, skid trails, landings, and parking areas within any CDF project area. Dirt roads provide excellent soil exposure and any major site crossed by existing dirt roads may be more visible than on the surface of the undisturbed portions along either side of it. Roads, landings, and staging areas are also locations that may receive disturbance from equipment to facilitate the project and any sites located near such areas are especially threatened. Focus your eye to be alert for anything unusual such as stream cobbles where they do not naturally occur or exotic materials brought into the area.
Where to Look
Proximity to Water: Most prehistoric sites, including villages and camp sites, occur near water sources. These may include springs, seeps, drainages, streams, rivers or ponds. Areas along small forested streams are excellent locations to find prehistoric archaeological sites. Surveys should always be intensified in areas adjacent to all watercourses to determine the presence or absence of archaeological sites. Where steams meander through alluvial valleys, oftentimes the most likely location for a site is not directly along the stream but back on the edge of the hillslope on slightly higher ground. This is often where timber operations will be conducted rather than within the open grassland. Many sites in the forest occur in direct association to springs, especially if these springs surface on or near flat or south-facing benches. After multiple years of drought, springs adjacent to archaeological sites may no longer exhibit surface water but usually still be detected by lush green vegetation such as sedges. Springs within timberlands are often developed into ponds for livestock or use by water trucks but the archaeological sensitivity of adjacent flat areas may be extremely in spite of the spring development. There is almost always a prehistoric site in the same location as a 10,000-gallon water tank.
Do not assume that all prehistoric sites occur near or adjacent to where water is present in some abundance today. This is not true and by not considering areas away from water, you will miss many sites. First one has to determine what ÒnearÓ means. It does not necessarily mean adjacent to the water, but can mean in the line of sight or within walking distance. There are many sites located near extinct water sources. Also, many ritual areas, trails, quarry areas, rock art sites, cemeteries, hunting blinds, defensive areas, and so forth and so on are not near water. Springs, streams, creeks, even ponds and lakes come and go over time, and even major rivers change their courses. If you ever survey immediately after a fire, you will be surprised at how many old springs re-emerge owing to the loss of capillary action of the burned trees and bushes- - - look for these re-emerging springs, for like as not, there will be a 6,000, 8,000 or even 10,000 year old archaeological site right next them, obscured by vegetation for the past 4,000 years.
One of the most likely locations for prehistoric archaeological sites in California is at the confluences of two or more streams. Typically, the site will be in the delta or ÒVÓ just upstream from the confluence, high enough to be above the high-water mark during the spring flood. This is the ancient California method of Òhedging your betsÓ- - if one creek goes dry, you still have a 50% chance that the other one will nevertheless be flowing. Villages or camps located at stream confluences are therefore twice as likely to survive than those completely reliant on but a single watercourse.
Topography: There are several common topographic settings for archaeological sites: ridge tops, mid-slope benches, and streamside terraces. Prehistoric sites usually occur on flat areas or gently sloping terrain, rarely on steeper slopes. Saddles on ridgelines are especially good locations for prehistoric sites, and often prehistoric foot trails can be found leading towards sites which were used as rest stops or way-stations in these natural passes through broken terrain. Sometimes the areas containing sites are not completely flat, but when compared to surrounding terrain, the places selected are usually flatter. River and stream terraces are logical places to look for prehistoric sites in California. These sites can be right on the river sand or cobble bars only a few feet above the water level, but if so, must be comparatively recent in age, for earlier sites would surely have been washed away or covered with alluvium via downstream transport. Prehistoric sites are much more commonly encountered on the first terrace upslope from the river or stream, which puts them above flood stage during normal years.
Historic sites and prehistoric sites associated with resource procurement (mining sites, chert quarries, etc.) do not always follow this pattern of favorable topography. Those sites typically occur where the best resources exist, and, particularly in the case of Historic sites, especially Gold Rush site, they may be where no sensible, subjective, surveyor would look for them.
Forest Openings: Most prehistoric archaeological sites in California's forests occur in or along the margins of natural openings. Sometimes sites are found in heavily forested areas, but natural openings were sought-out for use by prehistoric people, especially those with water sources nearby. The investigator should intensify the search within these openings and along their margins because California Indians favored these locations for settlements. Also, the ground visibility is often better here than it is under heavy forest canopy. Chances of finding a projectile point, mano or flake scatter are much improved when mineral soil can be seen. Likely areas covered with duff should be periodically troweled during the survey, especially low flat outcroppings.
Insolation: In the northern hemisphere, especially in mountainous areas with pronounced seasonality, south-facing slopes are the preferred locations for both prehistoric and historic site placement. South facing slopes get more hours of sunlight per day than east, west, or especially north-facing slopes, and in winter, less snow falls on them and stays on them for shorter periods than other areas.
Favorable Environmental Conditions: Sites often occur in settings that allowed people to exploit the local environment. For example, in the Sierra Nevada region, sites often occur at or near certain kinds of rock outcroppings, not just any rock, but bedrock or boulders with flat polished surfaces suitable for use as mortars. A typical Sierran site may contain a midden deposit, numerous bedrock mortars on granite exposures, surface artifacts, and perhaps, rock art. The presence of nearby oak trees is also a good indicator of archaeological sensitivity as they provided Native California people with their staple food – acorns. Prehistoric sites are common along ecotones. These are ecological communities of mixed vegetation formed by the overlapping of adjoining communities. Sites are often found here for exploitation of a variety of important resources within different vegetation zones.
A productive technique to evaluate where to look is to examine the project area from a distant viewpoint (such as an adjacent peak or ridgetop), evaluate the archaeological sensitivity of specific zones, and identify them on a map for careful inspection.
It is an unfortunate irony that road construction and facility improvements such as log landings, or parking areas, are the kinds of project activities that have the greatest potential to damage or destroy cultural resources, yet these facilities can also be helpful to find them by providing good exposure. The surveyor should always examine road cuts, road prisms, cut banks, and any other areas where soil is similarly exposed.
What to Look For
The proceeding information was designed to help you know how and where to look for archaeological evidence. Such evidence includes archaeological sites, features, and artifacts.
FEATURES: Midden: One of the best indicators of a prehistoric occupation site is midden. Midden is found at prehistoric sites throughout the world, not just within California. It is dark (often black) silty soil resulting from intensive, repeated use and habitation of the same area. The most distinctive characteristic of this soil is that it contains lots of soot, ash, and broken (fire-cracked) rocks from repeated campfires, and is different in color and texture from surrounding soils. Midden often (but not always) contains broken tools, burned bones, charcoal, waste flakes, cooking stones, broken milling equipment, and other evidence of habitation. However, careful study of midden constituents can reveal significant information about the people who once lived at a site. 
Rodents often burrow into midden deposits resulting in black back-dirt piles. This process can benefit an archaeological survey as the back-dirt piles expose midden enabling it to be identified. Sometimes, when grassy vegetation on a site is high, examination of rodent burrows is of crucial importance. Not all dark soil is midden. Sometimes natural processes occur which produce midden-like soil. These false middens are sometimes formed near springs and under oak groves, however, midden usually can be identified from the following characteristic attributes:
- It is localized - there is usually an abrupt soil color change in a relatively small area and is noticeably darker than surrounding soils just off the site.
- It has a sooty, ashy, greasy feel to it.When dry, a dark film sticks to your hands.
- It occurs at likely areas such as stream terraces, near springs, on ridgetops, etc.
Once you suspect that you may be seeing midden soil, you should carefully search for artifacts or other cultural remains that might confirm the identification. When you find dark silty soil and suspect it may be midden you should scoop a small handful and let it fall off your hand. Fine sticky dust will adhere to the fingers and palm of your hand. Natural dark soil does not. Another way to determine if the dark silty soil is midden is to carefully examine the surface for cultural materials including visible artifacts or surface features.
FEATURES: Housepits. Another important indication of prehistoric occupation sites are features, and the most common and easily recognizable kind of feature is the housepit. These are not found at all sites, but in many areas within California, such as Sonoma and Mendocino counties, and throughout the Sierra Nevada foothills, they are very common. Most housepits are circular depressions - the remnants of Native American structures or dwellings. Usually found in open areas in the oak woodland regions, housepits also occur in California's forests. It may be difficult to distinguish cultural housepits from possible natural occurrences such as a burned-out stump or a blown-down tree. The following attributes may help distinguish housepits from those features caused by natural processes:
- Housepit sites usually contain a cluster of circular depressions and are located on a flat open area near a water source. Natural pits are often found as single occurrences, possibly on sloping ground, and frequently within thick forest.
- Housepits usually, but not always, occur on sites with midden or surface artifacts.
- An earthen rim, hearth remains, or other remnants of the structure may be present.
There are three common sizes of housepits. The largest type, the dancehouse or roundhouse, may exceed fifty feet in diameter. These large depressions usually occur at or near major villages. Archaeological excavations of these housepits have revealed post holes, hearths, doorways, or hardened-clay floors. Another type of housepit is smaller than a roundhouse. Typically, this structure served as a dwelling for small family groups, and often measures from 10 to 15 feet in diameter. The most common type of housepit found during surveys of California's wildlands are small single family dwellings that are approximately 6-8 feet in diameter, and 1-2 feet deep. Housepit depressions found in far northwestern California (Humboldt and Del Norte counties) are usually rectangular in shape.
FEATURES: Bedrock Mortars Another archaeological feature to look for, especially in the Sierra Nevada region, is the bedrock milling station. The most common of these is the bedrock mortar (BRM). BRMs are circular holes or depressions ranging from 3 to 6 inches in diameter, and 2 to 28 inches deep. Many are conical in cross-section. A typical example is 5 inches wide and 4 inches deep, and occur in clusters on flat-topped rocks, boulders, or outcroppings. Sometimes these bedrock mortar panels are concealed by dirt or forest debris such as pine needles, logs, duff or grass, and need to be cleared. A trowel is a useful tool for archaeological surveys to aid the search for bedrock mortar pits. Look for pestles which were used with BRMs. A typical example is a large unshaped cobble - either triangular or roughly cylindrical, which exhibits use-wear on its pointed end or ends. Pestles in the North Coast tend to be well shaped, made of sandstone, and broader at the distal (the pounding) end.
Other milling features to look for include bedrock metates or grinding basins. These were used with manos or handstones to grind seeds and other foods. They can usually be easily seen as oval depressions with polished surfaces. Another type of milling feature is the bedrock "slick". These are very easily missed since often an oblique light is needed to reflect the polish from milling use. During a survey, rub your fingers or palm across suspected flat outcroppings to search for bedrock slicks. It is extremely important to seek out and examine all low flat rock outcroppings. Look for bedrock milling features, rock art panels, feel for slicks, use a trowel to poke and clear for mortars, and examine the surrounding soil for midden and artifacts, housepits, or other evidence.
FEATURES: Rock Art Another type of archaeological feature you should look for is prehistoric rock art. Most scientists classify rock art sites into two types. Petroglyphs are designs that are pecked, scratched or ground into a rock surface and pictographs are designs formed by the application of a substance such as paint or charcoal upon a rock surface. Some panels are both carved and painted. The surveyor should become familiar with the type of rock art that occurs in a given region and carefully examine similar rock surfaces.
ARTIFACTS: Flaked Stone The archaeological surveyor should also be carefully searching for chipped stone artifacts, especially waste flakes. These flakes are thin pieces of chipped stone discarded during tool manufacture. Some flakes simply represent chipping waste either angular chunks shattered from the core or discarded flakes. Some of the flakes are tools themselves. Flakes can be distinguished from naturally-formed thin pieces of broken rock. Look for exotic rock types (such as obsidian, chert, basalt felsite, etc.) and for a bulb of percussion, platform, ripples, or other traits characteristic of flint-knapping activity. In the Sierra Nevada, the most common types of chipped-stone materials are basalt, obsidian, chert, and quartz. Slate, andesite and vitrified tuff were also used. Franciscan chert and obsidian are the two most common materials found at sites in the North Coast Ranges.
ARTIFACTS: Ground Stone The artifacts found on a site are usually discarded waste items and therefore are often incomplete broken fragments. The careful observer must be able to recognize the complete form from fragmentary remains. One artifact type commonly found throughout California is the hand stone (or mano) and the mill (or metate). Hand stones are cobble tools that have one or sometimes two ground surfaces. They are used with a metate, mill, or grinding slab. These tools are usually found as fragments, are usually made of sandstone, vesicular basalt, andesite or other such materials with abrasive properties. Carefully examine possible mano and metate fragments by touch and sight for evidence of grinding.
ARTIFACTS: Other Surveyors must also be alert for artifacts and other items made of bone, shell, or pottery as these are also common occurrences at prehistoric sites within California.
