Neptunism

The theory, systematized by the German mineralogist and Freiberg Mining Academy professor Abraham Gottlob Werner in his 1787 Short Classification and Description of the Various Kinds of Rock, that nearly all rock, granite and basalt included, precipitated in sequence out of a single primordial global ocean as it receded, with the oldest, deepest rocks crystallizing first. It dominated geological teaching in the late eighteenth century through Werner's own students, but its central claim failed under field study: basalt, which neptunists classed as a late aqueous deposit, proved on close examination to be crystalline, insoluble and free of the fossils a marine sediment should carry, and observable lava flows showed basalt forming directly from molten rock. The theory lost ground through the early nineteenth century as field evidence for plutonism accumulated and Charles Lyell's Principles of Geology (1830) popularized the newer view, though modern geology's recognition that sedimentary rock genuinely does form by precipitation and settling in water is, in its narrower way, a partial vindication of what neptunism got right about sedimentary process even as its whole-crust claim was rejected.