STRUCTURE AND AFFINITIES OF LEPIDOSTROBI. 441 



stem of the plant ; — of the scales, which, being inserted into the axis, 

 support the individual male or female organs ; — and of the latter them- 

 selves. These tissues can only be displayed by slicing fossils in the 

 very best state of preservation, and in such as are changed into a more 

 or less transparent mineral. Specimens of this description are ex- 

 ceedingly rare, and have not hitherto been described. 



3. The two above considerations are secondary to the remaining one, 

 the nature of the contents of the cones. There may be stamens or 

 male organs, — ovaria, or female ones ;— or lastly, capsules containing 

 reproductive spores (which are peculiar to plants having no sexual 

 system) ; for these three kinds of organs all occur arranged in the 

 form of cones, undistinguishable from one another by any external 

 marks. Up to the present time no carboniferous fossil cone has ever 

 been known to supply this great desideratum, without which we can 

 arrive at no exact conclusion as to whether these curious objects are 

 clusters of flowers, or fruits, or are the spore-bearing organs of flower- 

 less vegetables as mentioned above. 



Sections of numerous fossil cones have been prepared for the Geolo- 

 gical Survey, with the view of illustrating these several points. Many 

 have hardly repaid the trouble and expense of slicing, whilst others, 

 which from external characters had been considered the least pro- 

 fitable, have, on the contrary, turned out the most instructive. It is a 

 fact, that neither the most experienced lapidaries, or collectors, nor 

 the geologists, mineralogists or botanists, have been able to decide in 

 the majority of cases by the external appearance of a fossil cone 

 how its internal and microscopical tissues shall be preserved. As an 

 instance, it may be mentioned, that the most beautiful of all the Lepi- 

 dostrobi which I have seen (that figured at plate 8, fig. 1) is utterly 

 worthless as a structural specimen. This circumstance, combined with 

 the rarity and singularly elegant forms of these plants, must ever render 

 their collection and investigation among the most attractive and curious 

 branches of Fossil Botany. 



The circumstances under which these structural specimens occur are 

 not the least interesting points in then' history. All are found in the 

 seams or nodules of clay iron-stone, and are very highly mineralized, 

 sometimes containing crystals of iron, and the cavities in their substance 

 being filled with white carbonate of lime and magnesia. Those which 

 are most complete always form the nuclei to nodules of clay iron- 

 stone — such are those figured at plate 7, and plate 8, fig. 1 ; but in these 

 the internal tissues are nearly obliterated. Others again, including all 

 in which the spores are preserved, have occurred as broken frustules, 

 within stems of Lepidodendron elegans and other species of that genus. 



I have examined as many as thirty specimens of cylindrical truncheons 



