S42 J. W. DAWSON ON A DIPLOXYLON FROM NOVA SCOTIA. 



by external markings, the number of kinds of gymnospermous fruits 

 and cryptogamous strobiles associated with them, and the great 

 range of organization presented by their stems, indicate a consider- 

 able variety of generic and specific types, probably bridging over, 

 by means of the class of Gymnosperms, the great gap at present ex- 

 isting between the Angiospermous and Acrogenous trees, and giving 

 an amount of diversity to the forests of the coal-period of which we 

 have as yet little conception. A further illustration of this is pre- 

 sented by the remarkable species of Cordaitts recently described by 

 M. Grand'Eury, and which furnish another varied series of Gymno- 

 spermous type. 



