This Field Guide is about the stone points that tipped the spears, darts and arrows made by the ancient inhabitants of what we now call Eastern Idaho. Collectively referred to as projectile points, they are of interest because they are the only artifact commonly found on archaeological sites that stylistically changed over time; therefore the accurate identification of point types provides an estimate of when they were made. This estimate is often the only information available to archaeologists about when sites were occupied. Points are so important that an entire culture history can be written about an area based on the discovered points, especially when their precise locations and their associated artifacts are adequately documented.

Projectile Point Chronology


The quickest way to identify a point is to browse through this guide starting with the outlines on the previous pages. First, decide which morphological group best represents its overall shape: notched, stemmed or lanceolate. Next, examine the point's base where it fastened to the shaft of the spear, dart, or arrow. Then browse through the outlines looking for the best resemblance and flip to the indicated page. Read the description and compare the measurements. There are large and small varieties of some of the shapes, and there are subtle differences between similar types so the measurements may be crucial. The various measurements are defined in the following pages.

Browsing can help identify many points, but if a point remains unclassified after browsing and comparing descriptions and measurements, go to the classification key(notched points, stemmed points, lanceolate points) at the beginning of the relevant section. Each key highlights the diagnostic characteristics that separate one type from another. The keys involve a series of dichotomous (two-branched) decisions, each representing two alternatives for one characteristic. Depending on the answer, proceed to either the step indicated or the point type. However, it must be remembered that ancient flintknappers were of varying skills, they used materials of varying qualities, and they probably had varying time constraints. They clearly had a size and shape in mind but the end product may diverge considerably from the ideal. Plus, points were broken either during manufacture or use, and if the damage was not major, the point may have been resharpened and reshaped rather than replaced. For all these reasons some points defy classification.



The archaeology of Eastern Idaho is unique due to its geography and location. It lies at the intersection of three major physiographic and environmental provinces of North America: the forested Columbia Plateau to the northwest, the desert Great Basin to the south, and the grassland Great Plains to the north and east. The Snake River Plain of Southern Idaho (with its tributary river valleys) has been the natural thoroughfare connecting these three areas throughout time, and its archaeology and history reflects this fact (witness that when early Euro-American pioneers headed for Oregon and California they traveled along this well established route now known as the Oregon Trail). Therefore, it is not surprising that many projectile point styles in the region are similar, if not identical, to points from one or more of the surrounding areas. A dilemma arises from this fact: often identical point styles have been given different names in the three areas. In Eastern Idaho the adoption of one or another of these names, or even the declaration of a new name, has progressed haphazardly and without rules or logic. This Guide uses commonly applied names in the region because they have become an integral part of the jargon of local archaeology. However, the selection and use of one name over others may imply affiliations and relationships that are unwarranted. But that is the nature and history of Eastern Idaho archaeology. Wherever possible, this Guide cross references the nomenclature common to surrounding areas. However, these cross references are admittedly incomplete and should not be considered exhaustive.


Archaeological surveys and excavations of archaeological sites in Eastern Idaho over the past 50 years have generated a rich collection of projectile points, a product of at least 13,000 years of human occupation. From this database, and from research completed in surrounding regions, it is clear that specific styles of points were made within limited time periods. It is also clear that many styles occur only within spatially bounded regions. The temporal and spatial patterns associated with the various styles provide a multidimensional framework in which archaeological sites can be organized, summarized and interpreted. And, Eastern Idaho has a unique aggregate of point types that is different than any of the surrounding regions. Even the outline of the “archaeological” Eastern Idaho as shown on the following map is the spatial distribution of a distinct projectile point type: the

Wahmuza Lanceolate. This outline also coincides with the traditional homeland of the Northern Shoshone and Bannock Tribes. The cohesion and uniqueness of the region extends back at least 4000 years into prehistory as documented by the chronology of the Wahmuza point. The Greater Eastern Idaho Archaeological Region

A classification key(notched points, stemmed points, lanceolate points) for projectile points for Eastern Idaho is presented in the following pages. The development of this key involved the statistical analyses of over 500 points associated with approximately 100 radiometric dates recovered from 17 excavated sites (Holmer 1995). In these sites, radiocarbon dates are not available for every stratigraphic level. Therefore, regression analysis comparing the existing dates against their depth below modern surface allows an estimation of dates for each artifact-yielding stratum. Hundreds more point fragments were recovered but are not sufficiently complete to be included in the statistical analyses upon which the following key is based.

Standardized attributes from digital images of the actual specimens were measured and calculated using computer software. Blade width, neck width, base width, and shoulder angle were measured; and the ratios of the various widths were computed. These four measurements, and their ratios, consistently and objectively segregate the major projectile point styles into temporally sensitive types. Other measurements were tested, such as thickness and length, but have been rejected because they do not improve the classification of points.



All archaeological sites are unique chapters in the history of human life on earth. When a site is destroyed, that unique glimpse is lost forever. Artifacts do not, alone, tell a story of those who have lived, loved and died in the past; it is the context in which the artifacts were left that tells most of the story. Therefore, it is critical that sites be preserved for future research as advanced methods and techniques become available to future archaeologists. It is important to note that the story presented in this Guide could not have been told if a few important sites were not scientifically excavated. If they had been destroyed by vandalism, we would not have the basic data upon which to develop an interpretation. So, please, do not dig for artifacts; and, if you know of or find a site that appears to have deep, buried, deposits, please contact the Department of Anthropology, Idaho State University. ISU will probably not be able to excavate the site, but should be able to assist in preliminary assessment and ultimate preservation of these invaluable and endangered resources.


Science is an approach to addressing questions; in the case of this Guide, the questions are about the characteristics and antiquity of the various styles of projectile points that occur in Eastern Idaho. The scientific approach involves collecting hard facts to support or refute interpretations. Science does not "prove" explanations; it can only disprove those interpretations that do not accurately explain the facts. However, a disproof may have to await the collection of new data, which may be a long time coming. As new data become available, refined interpretations are possible. Sometimes, entirely new interpretations replace the obsolete ones as the data base grows and new ideas come to mind. It is in this manner that science continually corrects erroneous ideas; and scientists assume that they will never achieve absolutely complete and correct answers.

The characteristics and age determinations presented here are nothing more than "hypotheses" waiting to be disproved. With the collection of more and more empirical data, we either gain confidence that the age determinations are reasonably accurate, or we revise our earlier hypotheses. However, we will probably never know, on a year-by-year basis, the total range of characteristics and exact time frames of each projectile point type. Therefore, this Guide is updated periodically, incorporating new information about projectile points and their ages as it becomes available. Look for future editions, and do not be surprised if new types are included, or new time ranges proposed. This is the nature of the science of archaeology.


This Guide is based on collections housed at the Idaho Museum of Natural History. It is important to realize that the collections are not "owned" by the Museum like we might own a car or a pocket knife. The Museum holds these collections "in the public trust" for research and educational purposes. Therefore, it is critical to maintain collections in public institutions like the Idaho Museum of Natural History because we all have access to the accumulating information, and it is preserved for our descendants to continue to build on the work of their predecessors.


It is illegal to remove artifacts from private, state or federal land without the written permission of the land owner or land administration agency. Violators have been prosecuted in court and convicted of theft of private or government property leading to stiff fines and/or jail sentences. On public land, they can also be prosecuted under the Archaeological Resource Protection Act and other laws. This Guide is not intended to encourage or promote illegal activities but is provided as a service to citizens who have funded archaeological research through their tax support of granting agencies such as the National Science Foundation and the National Endowment for the Humanities, and through land administration agencies such as the Bureau of Land Management and the U.S. Forest Service.

Although it is illegal to collect artifacts on public or private lands without proper authority, it is realized that most farmers, ranchers and others who work closely with the land have, over the years, amassed sizable collections that result from thousands of years of human use of the land and its resources. It is also recognized that professional archaeologists who receive public funding for scientific research have an obligation to share their findings and interpretations with the very public that funds their work. It is in this spirit that this Guide is provided.


All the drawings included in this Guide are borrowed from existing publications and reports; references are provided with each illustration and a

bibliography is included at the end. Photographs are digital images of points from excavated sites in eastern Idaho and are part of the database used to develop the following classification key. Occasionally the interpretations presented here are not those of the original authors, and I take full responsibility for the interpretations.

It should also be acknowledged that the format of this projectile point guide was heavily influenced by my favorite plant identification guide book (Kershaw et al. 1998). It is probably the most user-friendly and complete field guide for the region that I have encountered. Plus it has wonderful information about ethnobotany (the uses of plants by native people) which makes it doubly useful for archaeologists.


The accurate classification of projectile points involves making a few measurements on the features and landmarks illustrated in the following drawings:

Point Landmarks and Definitions

Four measurements are involved in classifying points although not all four apply to all styles. The four measurements are: 1) Blade Width – measured in millimeters at the maximum width of the blade above the neck, stem or base (measured on all point styles); 2) Neck Width – measured in millimeters at the narrowest width of the neck just below the blade (only measured on notched and stemmed styles because there is no distinguishable "neck" on lanceolate styles); 3) Base Width – measured in millimeters near the bottom of the base (measured on all styles); and 4) Shoulder Angle – measured in degrees from a horizontal line to the lower edge of the notch or base (measured on all styles although it is not an important variable except for a few lanceolate styles. It may also be useful for large notched points if the blade is completely missing). Since points are roughly symmetrical, the three measurements can often be estimated for broken points if portions of the opposite side are intact.

Width Measurements

Blade Width, Neck Width and Base Width can be easily and accurately measured by ruler or inexpensive calipers. However, accurately measuring the Shoulder Angle directly from the point is difficult, especially in the field. It is much easier to make accurate measurements from printed photos; and modern digital photography, personal computers, and printers make this possible. This said, with experience, most points can be quickly and accurately classified in the field using the illustrations and key included here. It is only the points that measure near the thresholds separating types that often need to be verified and reclassified using photos.

To accurately measure the Shoulder Angle on a photo printout, place a straight edge along the Shoulder and draw a line as shown in the illustrations below. Most shoulders are not straight, so the line should average out variations; and both shoulders should be measured and averaged for accurate classification. Next, draw a horizontal line that intersects the Shoulder lines, then measure the angle between the two lines (protractor template provided on next page). Be careful to always measure in the correct direction: from the Right Shoulder measure clockwise around the base to the left, and from the Left Shoulder measure counter-clockwise to the right. Then average the two measurements to factor out point asymmetry and errors in the placement of a truly "horizontal" reference line.

In review, to use the following key first decide which of the three basic styles best characterizes the point to be classified. Then go to that section(notched points, stemmed points, lanceolate points) of the key and proceed with the sequence of decisions based on the measurements discussed above. Using the measurements insures that that points will be accurately classified 98% of the time. But remember, some points are so unusual, unique, badly damaged, or poorly made that they are beyond classification.

Left and Right Shoulder Measurements and Average Angle

All content Copyright © 2009 by Richard N. Holmer
Informatics Research Institute