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On the Vegetation of the Carboniferous Period, as compared 

 with that of the present day. By Dr HoOKER, Botanist to 

 the Geological Survey of the United Kingdom. 



(Concluded from vol. xlv., p. 369.) 



As a field for botanical research, there is none so novel as the 

 coal-formation ; the few yards of shaft being more than equivalent 

 to the longest voyage, in respect of the amount and kind of differ- 

 ence between the vegetation the naturalist is acquainted with, and 

 that he seeks to understand. Whatever be the nature of the vege- 

 tation to which the botanist is transported, he commences by ob- 

 serving, — 1. What are the orders, genera, and species, of plants cha- 

 racterising the Flora; their mutual affinities, and their relations to 

 those of other countries ; their numbers, and the relative proportions 

 which the natural groups under which they arrange themselves, bear 

 to each other. 2. The geographical distribution of the species, &c. ; 

 their extension over the surface of the country ; and the replace- 

 ment of one kind by another. 3. The relations which may be 

 traced between the species and the soil, to which some are peculiar, 

 whilst others are common to it and to very diiferent soils ; the 

 quantity of moisture, heat, and light, they require, and the ef- 

 fects of a diminution or increase of any of these elements. 4. The 

 reciprocal influence of the whole mass of the vegetation upon the 

 surface it covers ; the new soil, or alteration of the old, produced by 

 its decay ; the extent and composition of accumulations of dead mat- 

 ter ; the particular kinds of plants contributing most largely to, and 

 the consequent nature of, such deposits ; the conservative influence 

 of the vegetation upon this deposit, which may be retained by roots, 

 and sheltered by foliage from the action of elements, which, in the 

 absence of these protections, would rapidly sweep it away. 



An enumeration of these points, viewed in their bearing on the 

 subject of the Coal-Flora, will shew how limited is our knowledge of 

 any one of them, compared with what might be acquired from a very 

 superficial examination of any recent flora, or with what the geo- 

 logist may obtain from any inspection of the animal remains in many 

 strata. 



1. Of the mutual affinities of the groups under which the majo- 

 rity of the genera of coal-plants arrange themselves, little more can 

 be said, than that the Ferns occupy the lower end of the series, and 

 the ConifercB possibly the highest ; but this depends upon the view 

 taken of the affinities of Sigillarice, the most important group. These 

 are classed by some observers amongst Ferns ; by others, with Coni- 

 fertE; another considers them as linking these two widely-different 

 families ; whilst a fourth ranks them much higher than either. The 

 affinities of another group. Catamites , are entirely unascertained. Of 



