REVIEWS 779 



Elements de Paleobotanique . By R. Zeiller. 8vo, pp. 421, with 

 210 illustrations. Paris: Georges Carre et C. Naud, 1900. 



The great needs of recent years in Paleobotany have been a sum- 

 mary of'the scattered materials and the delimitation of well-founded 

 data from data that are more or less uncertain. A great stride for- 

 ward has been taken along these lines and as a result we are in a posi- 

 tion to speak more categorically as to plant fossils. The first part of 

 Professor Seward's work appeared sometime ago and has been reviewed 

 in these pages 1 . Almost simultaneously three valuable works have 

 recently appeared, one in English by Professor Scott, one in German 

 by Potonie, and the one which is the subject of this review. The 

 standpoint of the three works is somewhat different, Scott taking the 

 standpoint more of the morphologist, Potonie of the stratigrapher, 

 while Zeiller combines the botanical and geological standpoints, though 

 giving more emphasis to the botanical side. More than any book that 

 has yet appeared, this is a book to be used with impunity by general 

 readers and elementary students. The first chapter treats of the vari- 

 ous methods by which plant fossils have been preserved, then follows 

 a chapter on classification and nomenclature. The body of the book, 

 of course, is made up of descriptions of the various fossil forms treated 

 in order. The cuts are simple but clear and good, and the descrip- 

 tions are doubtless the shortest and clearest that are found anywhere. 



The conservatism of the author is shown at many points, and the 

 difference between established and hypothetical data is clearly brought 

 out. As an illustration of this, Zeiller constantly distinguishes between 

 forms based on leaves and forms based on reproductive organs, as in 

 the ferns. There are interesting discussions of the Sphenophyllese 

 and the Cycadofilices, though the author does not go so far as some in 

 putting these forms in great groups by themselves. 



At the close of the book are two chapters of extreme interest. 

 The chapter on the succession of floras and climates is wonderfully 

 meaty, and it is doubtful if a better summary of the known facts was 

 ever written, certainly not in a shorter compass. The author theorizes 

 but little from the facts presented, and such deductions as he makes 

 in regard to climate are extremely conservative. The last chapter 

 must be somewhat startling to many readers, as Zeiller thinks there is 

 very little evidence from fossil plants in favor of gradual evolution. 

 He states that in almost every case, species, genera, families, and 



'Jour. Geol. : Vol. VI, p. 436, 1898. 



