In this study, we analyzed the fossils and rocks of the formations Santa and Carhuaz of Cretaceous age found in the towns of San Marcos and Cajamarca determining its age and condition of their deposition. The determination of the relative heavy middle position (PMPR) of the sandstones of the fm. Carhuaz determined regional depositional characterization. It should be noted that both the fm. Santa as Carhuaz Miocene intrusive contact often behave as good host rocks for mineralization events, such as reservoir type Cu-Mo Porphyry El Galeno, located in the Department of Cajamarca. The fm. Santa, a name given by [1] of Cretaceous age, consists of an alternation of dark gray claystones and calcareous siltstones of marine transgressive character, lies in keeping on-shore beach sands of the fmcontinental. Chimú. According to [2] this machine exhibits regionally significant facies change, while ...