Abstract Throughout his life, Lyell travelled extensively, always as a keen observer. He viewed the Earth's geological history as continuous with and subject to the same processes of change as at present. Leopold von Buch's theory of craters of elevation contradicted Lyell's view of Earth history. Thus Lyell travelled to Madeira and the Canary Islands in 1853 to see von Buch's evidence. Lyell found the islands formed by a long series of volcanic eruptions, not by the single explosive upheaval that von Buch had described. Nevertheless, Lyell still accepted Léonce Élie de Beaumont's claim that lava flows could not form compact rock on steep slopes. In 1855, Lyell learned from Eilhard Mitscherlich that on Stromboli contemporary steeply inclined lava flows were forming solid rock. In 1857, Lyell went to Sicily where unmistakable evidence contradicted Élie de Beaumont. In the walls of the Valle del Bove, steeply inclined layers of lava were intersected by dykes that pointed towards a former centre of eruption at Trifoglietto, later buried by volcanic rocks emitted from the present centre of eruption at the summit of Etna, proving that the Valle del Bove could not have originated as a crater of elevation.

Abstract Fluid content: source of data – fluid distribution – fluid contacts. Water: classification – character – oil-field brines. Oil: measurement – chemical properties – physical properties. Gas: measurement – composition – impurities. THE RESERVOIR is that portion of the rock or rock layers that contains the pool of petroleum. So far we have discussed the reservoir rock and the spaces within the reservoir rock that contain the reservoir fluids; now we will consider the fluid content of the reservoir: the water, oil, and gas. Except for the relatively small volumes of permeable rock containing oil and gas pools—oil and gas reservoirs—nearly all of the pore space of the upper few miles of the earth’s crust is filled with water; the oil and gas occur in a water environment. Not only did they pass along water-lined permeability highways to accumulate into pools, but the pools of oil and gas generally are separated from the rock walls of the reservoir by a film of water. Consequently, petroleum geologists are much interested in the water content of the rocks, even though their objective is to find oil and gas. In this chapter we will consider the fluids water, oil, and gas as they occur in oil and gas pools. The disseminated occurrences, migration, and accumulation of petroleum into pools— the pre-pool history—will be considered later, in Chapter 12 .