the purpose of this thesis is to provide a framework for evaluating bison mobility in the eastern great basin during the thirteenth-century using strontium (sr) isotope analysis. the promontory caves, utah (42bo1 and 42bo2) were occupied for a relatively short period (a.d.1250-1290) but have a rich record of incredibly well-preserved organic remains including a high abundance of bison remains indicating that bison were a key prey species. previous research indicates a decline in the local bison population which may have triggered a push for ancient people to navigate the landscape to shift their home (or seasonally-used territory). one possible site that the promontory people visited is west fork rock creek (wfrc) (10-oa-275), idaho. there is evidence that wfrc was visited by promontory people as they were hunting bison in the late thirteenth-century. [...]