Archaeologists in North America often think of the bow and arrow as appearing more or less instantaneously, a conception baked into many culture-historical schemes. However, this specialized technology likely has a more complex history. From a single Old World origin, it is thought to have spread throughout North America from the Arctic after about 5000 cal BP. From there, it seems to have moved from north to south, but the specific timing of the arrival of this important technology is not known in great detail throughout most of California. Rather than using typological or culture-historical categories to discern this technological replacement, this study plots salient artifact attributes from a large sample of projectile points from central and northern California through continuous time to provide more detail on the timing of the spread of this important prehistoric technology. Results suggest the bow and arrow entered northeastern California before 2000 cal BP and moved southward, arriving at the Sacramento–San Joaquin Delta as much as 1,000 years later. The changepoint analysis method introduced here should be broadly applicable to a wide variety of similar archaeological patterns.

With generous support from the National Science Foundation, we have spent the past four years developing an archaeological radiocarbon database for the United States. Here, we highlight the importance of spatial data for open-access, national-scale archaeological databases and the development of paleodemography research. We propose a new method for analyzing radiocarbon time series in the context of paleoclimate models. This method forces us to confront one of the central challenges to realizing the full potential of national-scale databases: the quality of the spatial data accompanying radiocarbon dates. We seek to open a national discussion on the use of spatial data in open-source archaeological databases.