Revieivs. — Prof. Dana — On Palceozoic Botany. 17& 



vegetation may (even) Lave been as profuse for the amount of land, 

 although the circumstances were less favourable for its growth and 

 accumulation in marshes, the essential prerequisite for the formation 

 of large beds of coal." (op. cit. p. 297.) 



" The same genera of plants are represented among the European 

 coal-beds as occur in America ; and very many of the species are 

 identical." " In this respect, the vegetable and animal kingdoms are 

 in strong contrast ; for the species of animals common to the two 

 continents have always been few." (op. cit- p. 347.) 



" The genera Catamites, Sphenopteris, Pecopteris. Lepidodendron, 

 and Sigillaria, have much the largest number of species in Europe." 



" Exclusive of fruits, there are about four hundred and thirty- 

 four known American species and four hundred and forty European 

 (and British) ; and of these one hundred and seventy-six are common 

 to the two continents. In other words, about two-fifths of all the 

 American species were also growing in the Carboniferous forests of 

 Europe." (op. cit. p. 349.) 



" Coniferous trunks and stumps are- common through the Coal- 

 measures. Cordaites are strap-shaped leaves, half an inch to an 

 inch and a half wide, sometimes short, as in the Devonian species 

 [Cordaites Bobbii), and sometimes afoot or more long. They are 

 often crowded together in great numbers in the slates overlying 

 the coal-beds, and are common in other positions, thus showing that 

 they were shed in great numbers by some plants of the period. 



...■-yif':.- 



Fig. 1. Cardiocarpus elongatus. — Fig. 2. Card, biseotus — Fig. 3. Card.samarcz- 

 formis. — Fig. 4. Welwitschia mirahilis, showing transverse section of fruity with the 

 outline of the fruit finished in dotted lines. [Reproduced by permission from Dana's 

 Manual of Geology, Revised edition, 1874, p. 328.] 



They have been referred both to the Lepidodendrids and to the 

 Cycads, and by Schimper are embraced in Brongniart's genus 

 Pycnophyllum, under the latter order. Geinitz has observed in 



