94: 



SCIENCE, 



[Vol. V., No. 104. 



scarcely been conceived ; but continued failure to 

 correlate fossil witb living forms, even after thorough 

 examination of many tropical floras, began to give 

 importance to this question, and in the first year 

 of the present century Baron von Schlotheim com- 

 menced to urge for plants, what Blumenbach had for 

 some years insisted upon for animals, that the fossil 

 forms were extinct, and belonged to another age of 

 the world, characterized by a different kind of life. 

 Hard as this doctrine then was for the beliefs of the 

 times, its manifest soundness caused it steadily to 

 gain ground, and soon opened the way for the serious 

 study of paleontology on a true scientific basis. 



The reaction against attempting to correlate fos- 

 sil with living plants went too far, and the former 

 nomenclature was completely abandoned. Judging 

 all by the paleozoic forms, which had been the chief 

 objects of study, all efforts to apply generic names 

 even to those of the most recent formations were 

 suspended, and resort was had to the terminologies 

 of the mineralogists, particularly those of Waller, 

 Walch, and Schroter. All vegetable remains were 

 called phytolithes. Impressions on the rocks were 

 distinguished as phytotypolithes. Fossil leaves were 

 named bibliolithes, and fossil fruits carpolithes. Not 

 until 1818 did any one venture to establish species 

 under any of these heads. The first attempt of this 

 nature was made in that year by the Rev. Henry 

 Steinhauer, whose now celebrated memoir, ' On fossil 

 reliquia of unknown vegetables in the coal strata,' 

 describes and figures ten species of Phytolithus, as- 

 signing to each an appropriate specific name. This 

 may be regarded as the true birth of systematic 

 paleobotany, — an example of the humility of true 

 science as contrasted with the arrogant assumptions 

 of Scheuchzer a century before. 



It is remarkable that this initial paper by Stein- 

 hauer was published in an American serial, the Pro- 

 ceedings of the American philosophical society, at 

 Philadelphia, and was contributed by an American 

 citizen, and member of that society. But that it was 

 founded on any extensive study of the coal-plants of 

 this country, as some have stated, there is no inter- 

 nal evidence. No American localities are mentioned ; 

 and the paper seems to deal throughout with British 

 fossils and British coal-mines, with which the author 

 was perfectly familiar. 



Schlotheim, who in his 'Flora der vorwelt,' 1804, 

 had not dared to go thus far, took a step in advance, 

 two years later, in his ' Petrefactenkunde.' He 

 greatly enriched the terminology of the science, and 

 described with true binomial designations seventy- 

 eight species belonging to seven genera of fossil 

 plants. 



Count Sternberg's 'Flora der vorwelt' commenced 

 to appear in parts at about this time, in which many 

 new genera were created on thoroughly studied 

 grounds; and in 1822 Adolphe Brongniart's elaborate 

 paper on the classification of fossil plants was pub- 

 lished in the memoirs of the Paris museum of natu- 

 ral history. But these contributions, though highly 

 systematic, and by far the most important that had 

 been made to the science, did not descend to the 



question of species, nor indicate the number of dis- 

 tinct forms. The next work, therefore, in which 

 light is thrown upon this problem, was Brongniart's 

 ' Prodrome,' which appeared in 1828. By this time 

 the science of paleontology had been fairly estab- 

 lished, and geognostic considerations had come to 

 receive something like their due weight. The ancient 

 floras were distinguished from the later ones, and 

 the approaching analogy of the latter to that of our 

 own time was clearly perceived by Brongniart, who 

 thus early prophetically declared for the successive 

 development of higher types, though this view was 

 strenuously opposed by the English school a decade 

 later. 



In this work, and the large treatise published the 

 same year ( ' Histoire des vegetaux fossiles ' ), to which 

 it forms an introduction, an immense advance was 

 effected in the systematic treatment of fossil plants. 

 Not only was a large number of species recognized, 

 belonging to the extinct genera heretofore estab- 

 lished, and many new genera created, but the iden- 

 tity of many of the fossil with living genera was 

 boldly asserted, at least for the more recent forma- 

 tions; and a long step was taken in the direction 

 of correlating the extinct and living floras, and of 

 demonstrating the fact of an uninterrupted series 

 connecting the past with the present plant-life of 

 the globe. 



At that date Brongniart enumerates five hundred 

 and one species of fossil plants, nearly half of which 

 belonged to the first, or oldest, of his four periods, 

 corresponding to the paleozoic of modern geologists, 

 and of course chiefly from the coal-measures. 



It is interesting to note here how much faster the 

 science of fossil plants has advanced in this numeri- 

 cal respect than that of botany proper; for, while 

 more than a hundred living species were then known 

 to Brongniart for every fossil species, only eighteen 

 living plants are now known to one fossil plant. 

 And yet how rapid has been the growth of our 

 knowledge in both sciences may be realized by con- 

 templating the fact that nearly five times as many 

 living, and sixteen times as many fossil, plants are 

 recognized now as then. 



A census of fossil plants was again taken in 1845, 

 by Unger, in his ' Synopsis plantarum fossilium,' in 

 which he enumerates 1,648 species; and in the same 

 year, by Goppert, quite independently of the former 

 work, in a paper published in Leonhard and Bronn's 

 'Neues jahrbuch fiir mineralogie,' in which 1,778 

 species are claimed. Sixty-eight thousand living 

 species were then known to Goppert, or about thirty- 

 eight living to one fossil species. 



In 1849 Goppert again reviewed the fossil flora, 

 and published an exhaustive enumeration in Bronn's 

 ' Index palaeontologicus.' He now finds 2,055 fossil 

 species, to be compared with the 69,403 living species 

 named in the same work, or less than thirty-five liv- 

 ing to one fossil species. 



The third quarter of the present century was one 

 of intense activity for systematic vegetable paleon- 

 tology. The combined labors of Heer, Saporta, Et- 

 tingshausen, and Lesquereux, with a large corps of 



