A study was conducted to confirm the presence of zeolites and determine the type of zeolite minerals associated with the subsurface volcanic province in Humphreys, Leflore, and Holmes Counties, northwestern Mississippi. The petrographic microscope and x-ray diffraction with the gandolphi camera were the primary tools used to identify the minerals. The most abundant zeolite mineral was analcite. Natrolite and chabazite were both suspected as minor mineral components in several locations. Other minerals such as celestite, ankerite, and clay (illite type) were found in the process of looking for zeolites. The abundant presence of analcimite indicates that the temperature regime associated with volcanism is relatively low, probably no higher than 120 deg to 130 deg c, which is not enough heat to degrade hydrocarbons to a noncommercial state. Study results indicate that thermal contribution to the trapping system by past volcanic events in the area does not increase the risk of successful oil well drilling.