Crude oils of Cretaceous, Jurassic, Mississippian, and Devonian age of western Canada were analyzed for Mg, V, and Ni. The method of analysis is given. The Mg content relative to Ni fell in the range of 60% to 1%. The Mg content relative to V ranged from 70% to 1%. A chart shows the content of Mg, V, and Ni in crude oils plotted as a function of time.