The Permo-Triassic Gondwana rocks in Uruguay have deficient faunal and floral characteristics, as compared with rocks of the same age in southern Brazil. They are also relatively incomplete stratigraphically. The general shallowness of the sedimentary basin, as seen by surface study and proved by drilling, makes hardly possible the accumulation of oil in commercial amount. It is probable that faults and fractures penetrating most of the sedimentary formations, and many diabases, both intrusive and extrusive, would have come into contact with any oil sands if such had existed underground and would have brought to the surface, either along fracture planes or formational contacts, some indications of the existence of oil, gas, or salt water. This conclusion seems especially easonable when the shallowness of the sedimentary basin is considered. The same factors and conclusions apply to the Devonian area where the Carmen sandstones and overlying shales are thinly covered by Gondwana sediments and do not reveal any favorable surface indications.