Vulcanists & Neptunists

To the Editors:

The review of The Discovery of Time by Stephen Toulmin and June Goodfield, included a sentence written “…in order to show how high the standard of the authors’ accuracy is.” The reviewer, Gavin de Beer, states that Guettard’s recognition of the volcanic nature of rocks in the center of France was important “because it clipped the wings of the ‘Neptunists’ who attributed everything in the Earth’s crust to the effects of Noah’s Flood.” Although Guettard was indeed the first (1752) to recognize the extinct volcanic features of central France and thus became the founder of the vulcanist school, he also eighteen years later in 1770 wrote a paper proposing that basalt originated as a precipitate from an aqueous fluid. This made him midwife at the birth of neptunism, rather than its gravedigger. The neptunists did not deny the existence of volcanoes but argued that basalt was not a volcanic rock and that volcanoes were recent and modern features, rather than ancient. Nor is it correct to characterize the neptunists as deriving their geology from the Bible. The foremost neptunist, Abraham Gottlob Werner, was probably the single man most responsible for the concept of the geological time scale. As professor at Freiberg beginning in 1775, after, rather than before Guettard’s work, he trained the students who, returning to their own countries, spread the new science which he called “geognosy” but they called “Wernerism” and “Neptunism.” The correct designation of the early naturalists who tried to reconcile their observations with Genesis is “diluvialist.” They did not attribute “everything in the Earth’s crust to the effects of Noah’s Flood” but only the superficial and obviously or apparently water-lain deposits. There were, of course, fundamentalists writing then even as now, but on the whole those of our predecessors in the vineyards of science who concerned themselves with matters geological were possessed of more historical consciousness than their contemporaries.

Cecil J. Schneer

Professor of Geology

University of New Hampshire

Durham

Sir Gavin de Beer replies:

It was not in 1752 but in 1751 that Guettard recognized the volcanic nature of the Puy de la Nugère and the lava flow descended from it near Volvic, as well as some seventeen other neighboring volcanic craters and domes. His paper in the Mémoires de l’Académie Royale des Sciences for the year 1752 (when he read it) was published in 1756. It is true that Guettard subsequently advocated an aqueous origin for basalt, but there was neither reason nor space for me to refer to this, because I was concerned only to correct the curious story spread by George Poulett Scrope, that Guettard’s attention was first drawn to the existence of extinct volcanoes in France, from the paving stones at Montélimart, by a group of scientists, including Faujas de Saint-Fond who, then, was ten years old. Faujas later tried (on the strength of a letter by Jean-François Ozy which he printed) to deprive Guettard of his priority by ascribing the discovery of the volcanoes of Auvergne to William Bowles and Johann Lucas Woltersdorff in 1750. This, also, was irrelevant to me, because I disbelieve this story, whereas Guettard’s discovery led to visits to Auvergne by Nicolas Desmarets, Frederick Augustus Hervey, John Strange, and others who placed Vulcanism on a sound footing, and this is why Guettard is the first known Vulcanist, who virtually founded the school.

The symmetrical antonym to Vulcanist is Neptunist, and this is why I used that word, which appears to be older in the English language than Diluvialist. As for diluvialists attributing only the superficial and obviously or apparently water-lain deposits of the earth’s crust to Noah’s Flood, John Woodward, in his Essay Toward a Natural History of the Earth published in 1695, got over the difficulty that fossils are found at great depths beneath the surface by assuming that “the whole terrestrial globe was all taken to pieces and dissolved at the deluge.” It is true that all “Neptunists” (and I used quotation marks on purpose to show that the word was taken in a wider context) did not subscribe to the diluvialist view but it is also true that Guettard was the man primarily responsible for the break-through that clipped the wings of those who did, and of those who did not, like Warner, Saussure, and Jameson, but held that igneous rocks were precipitated out of aqueous media.