AbstractThe notion that Paleoindians used bifaces as “mobile cores” is widespread in Late Pleistocene lithic research, although it can be difficult to test empirically. Here, we use experimental replication to establish two quantitative predictions that would be indicative of biface-core transport. If bifaces are being used as mobile cores, then we should see among a group of sites of varying toolstone procurement distances (a) a negative relationship between toolstone procurement distance and the mean unifacial tool maximum-thickness value from each site; and (b) a negative relationship between toolstone procurement distance and the variability (standard deviation) of maximum flake thickness values from each site. We then test these predictions against data from six Clovis sites of varying toolstone procurement distance in the Lower Great Lakes region. The results show that both sets of data possess a strong, positive relationship with increasing toolstone procurement distance, which is inconsistent with the notion that biface-cores were transported. Since the Clovis presence in the Lower Great Lakes is widely acknowledged to be a colonization pulse, we conclude that the lack of biface-core transport there is an economizing and risk-mitigating behavior consistent with the models of Kuhn (1994) and Meltzer (2002, 2003, 2004).