shells and fishes to be due to a "plastic virtue, latent in the earth," as Theophrastus had suggested long before. Lhwyd, in his "Lithophylacii Britannici Ichnographia," published in Oxford in 1699, gives a catalogue of English fossils contained in the Ashmolean Museum. He opposed the vis plastica theory, and expressed the opinion that the spawn of fishes and other marine animals had been raised with the vapors from the sea, conveyed inland by clouds, and deposited by rain, had permeated into the interior of the earth, and thus produced the fossil remains we find in the rocks. About this time several important works were published in England by Dr. Martin Lister, which did much to diffuse a true knowledge of fossil remains. He gave figures of recent shells side by side with some of the fossil forms, so that the resemblance became at once apparent. The fossil species of shells he called "turbinated and bivalve stones," and adds, "either these were terriginous, or, if otherwise, the animals which they so exactly represent have become extinct."
During the seventeenth century there was a considerable advance in the study of fossil remains. The discussions in regard to the nature and origin of these objects had called attention to them, and many collections were now made, especially in Italy, and also in Germany, where a strong interest in this subject had been aroused. Catalogues of these collections were not unfrequently published, and some of them were illustrated with such accurate figures, that many of the species can now be readily recognized. In this century, too, an important step in advance was made by the collection and description of fossils from particular localities and regions, in distinction from general collections of curiosities.
Casper Schwenkfeld, in 1600, published a catalogue of the fossils discovered in Silesia; in 1622 a detailed description of the renowned Museum of Calceolarius, of Verona, appeared; and in 1642 a catalogue of Besler's collection. Wormius's catalogue was published in 1652, Spener's in 1663, and Septala's in 1666. A description of the Museum of the King of Denmark was issued in 1669, Cottorp's catalogue in 1674, and that of the renowned Kirscher in 1678, Dr. Grew gave an account in 1687 of the specimens in the Museum of Gresham's College in England; and in 1695 Petiver, of London, published a catalogue of his very extensive collection. A catalogue by Fred. Lauchmund, on the fossils of Hildesheim, appeared in 1669, and the fossils of Switzerland were described by John Jacob Wagner in 1689. Among similar works were the dissertations of Gyer, at Frankfort, and Albertus, at Leipsic.
Steno, a Dane, who had been Professor of Anatomy at Padua, published in 1669 one of the most important works of this period. He entered earnestly into the controversy as to the origin of fossil re-
- "De solido intra solidum naturaliter contento."