Abandoning a promising career in the law, Barthelemy Faujas de Saint-Fond (1741-1819) enjoyed the encouragement of the eminent scientist Buffon in pursuing his love of natural history. His keen interest in rocks, minerals and fossils led to a number of important discoveries, among which was confirmation that basalt was a volcanic product. Appointed assistant naturalist at the natural history museum in Paris, he became a professor of geology in 1793, occupying this position until his death. This 1784 work begins with concise accounts of numerous varieties of basalt, describing the key features...