126 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



monograph of the plant impressions in the Carboniferous forma- 

 tion on the Thuringian districts, and was quite the best work 

 on fossil plants that had appeared. Schlotheim concluded 

 that, in spite of the resemblance between the tree-ferns of the 

 Carboniferous formation and certain East Indian and American 

 ferns, the fossil types belonged to extinct genera and species. 

 The same was, he said, true for the other forms of Carbon- 

 iferous plants, and it was possible that the fossil flora of the 

 Carboniferous epoch represented a wholly extinct plant-world. 

 Schlotheim left it an open question whether, in this case, the fossil 

 genera had died out, or whether their descendants had become 

 so much modified that they could scarcely be recognised as 

 such. 



Schlotheim's later work, his Petrefaktenkunde^ published in 

 1820, enumerated and described the fossil specimens in his 

 private collection. At the same time, in its plan it formed a 

 continuation of his previous work, and the fifteen quarto plates 

 of the Carboniferous flora were incorporated, together with 

 twenty-two new plates, to illustrate the larger work. The 

 plates were admirably carried out, and the specimens, which 

 included all types of animal life, were for the first time in 

 Germany named according to the binomial nomenclature. 

 Hence the work has had a permanent value in literature, 

 although it is true the descriptive text is often insufficient, and 

 a species can be ^identified only by comparison with Schlot- 

 heim's originals, which have been preserved in the Berlin 

 Museum. 



Faujas de Saint-Fond's works on fossil organisms can scarcely 

 be compared with those of Schlotheim. The first volume of 

 his Essay on Geology (Paris, 1803) is devoted almost exclu- 

 sively to fossils. But he held the narrow, antiquated opinion 

 that the great majority of fossil forms represented existing 

 species of plants and animals, while the few forms for which 

 no living analogues were forthcoming probably belonged to 

 species now living in unexplored portions of the globe. 



Defrance was one of the most industrious and careful of the 

 early palaeontographical annotators. In his Sketch of Fossil 

 Organisms (Paris, 1824) he gave a short account of all known 

 fossils, with accurate mention of their localities and state of 

 preservation. Between 1816 and 1830 he contributed to the 

 Dictionary of Natural Science numerous treatises on fossil 

 foraminifers, corals, molluscs, annelids, and echinids. 



