At that time many distinguished foreign geologists were working at the Alps; but little of conclusive importance had been published, except in papers embedded in Transactions of various societies. Professor Alphonse Favre's great work did not appear until 1867, and the "Mechanismus der Gebirgsbildung" of Professor Heim not till 1878; so that for an English public the subject was a fresh one. To Ruskin it was familiar: he had been elected a Fellow of the Geological Society in 1840, at the age of twenty-one; he had worked through Savoy with his Saussure in hand nearly thirty years before, and, many a time since that, had spent the intervals of literary business in rambling and climbing with the hammer and note-book. In the field he had compared Studer's meagre sections, and consulted the available authorities on physical geology, though he had never entered upon the more popular sister-science of palaeontology. He left the determination of strata to specialists: his interest was fixed on the structure of mountains--the relation of geology to scenery; a question upon which he had some right to be heard, as knowing more about scenery than most geologists, and more about geology than most artists. As examples of Savoy mountains this lecture described in detail the Salève, on which he had been living for two winters, and the Brezon, the top of which he had tried to buy from the commune of Bonneville--one of his many plans for settling among the Alps. The commune thought he had found a gold-mine up there, and raised the price out of all reason. Other attempts to make a home in the châteaux or chalets of Savoy were foiled, or abandoned, like his earlier idea to live in Venice. But his scrambles on the Salève led him to hesitate in accepting the explanation given by Alphonse Favre of the curious north-west face of steeply inclined vertical slabs, which he suspected to be created by cleavage, on the analogy of other Jurassic precipices. The Brezon--_brisant_, breaking wave--he took as type of the billowy form of limestone Alps in general, and his analysis of it was serviceable and substantially correct.