EXPLANATIONS. 



negative at the best ; and it says as much for the non- 

 preservation of mosses and other humble plants as for 

 dicotyledons. It has also been remarked that, consider ^ 

 ing such facts as the disappearance of equisetum hyemala 

 in water, a plant containing an unusual quantity of silex, 

 " the proportion of fossil plants in each formation must 

 depend on other circumstances besides their power of re- 

 sisting decomposition."* " Too much importance has," 

 in the opinion of the author of this observation, " been 

 attached to Dr. Lindley's experiments." 



The British Quarterly Review says — *' The author 

 admits there were dicotyledons among these plants, and 

 does not see that, however few they may be, it entirely 

 upsets the theory of progressive advance, especially in the 

 absence of any proof as to whether they were created 

 first or last." This proceeds, as do many similar objec- 

 tions, upon the idea that a formation represents one point 

 in time. A formation, in reality, represents many years, 

 or rather ages. Such expressions as that simple and 

 complex plants occur together in the carboniferous for- 

 mation, or even (shall we say) in its first fossil bands* are 

 vague expressions, perhaps conveying an idea substan- 

 tially false. There is no such precision in the ascertain- 

 ed relations o^fossils to particular strata, as to entitle any 

 one to say that the simple and complex plants of this for- 

 mation are rigidly contemporaneous. They may have 

 followed each other within the space of -half a century in 

 a particular region, and yet been preserved in but one 

 stratum, or little group of strata. The actual appear- 

 ances of the carboniferous formation thus, perhaps, allow 

 full time for a progressive advance in particular regions, 

 from the fleshy luxuriant plants of the marsh and low 

 sea margin to the robust tree of the more elevated re- 

 gions. We must remember, too, that the vegetation oi 

 the carbonigenous era, even if we take it back to include 

 the confer said to have lately been found in the Old Rett 

 of Cromarty, or the fern leaf of the Silurians, was pre- 

 ceded by unequivocally simple plants in the fucoids. 

 Starting with these, and finding the first great burst c/ 

 land vegetation composed mainly of low cryptogamic and 

 monocotyledonous plants, — finding, moreover, the ex- 

 ceptions chiefly of the intermediate character, and thai 



* Mr. C. J. Bunbury, at the British Association, 1845 j Athen» 

 urn's Report. 



