358 LIFE AT DOWN. JETAT. 33-45. [1847. 



upright in situ, of course I must give up the ghost. But 

 surely Sigillaria is the main upright plant, and on its obscure 

 affinities I have heard you enlarge. 



Thirdly, it never entered my head to undervalue botanical 

 relatively to zoological evidence ; except in so far as I 

 thought it was admitted that the vegetative structure seldom 

 yielded any evidence of affinity nearer than that of families, 

 and not always so much. And is it not in plants, as certainly 

 it is in animals, dangerous to judge of habits without very 

 near affinity. Could a Botanist tell from structure alone that 

 the Mangrove family, almost or quite alone in Dicotyledons, 

 could live in the sea, and the Zostera family almost alone 

 among the Monocotyledons ? Is it a safe argument, that be- 

 cause algae are almost the only, or the only submerged sea- 

 plants, that formerly other groups had not members with such 

 habits ? With animals such an argument would not be con- 

 clusive, as I could illustrate by many examples ; but I am 

 forgetting myself ; I want only to some degree to defend my- 

 self, and not burn my fingers by attacking you. The foundation 

 of my letter, and what is my deliberate opinion, though I dare 

 say you will think it absurd, is that I would rather trust, c&teris 

 paribus, pure geological evidence than either zoological or 

 botanical evidence. I do not say that I would sooner trust 

 poor geological evidence than good organic. I think the basis 

 of pure geological reasoning is simpler (consisting chiefly of 

 the action of water on the crust of the earth, and its up and 

 down movements) than a basis drawn from the difficult 

 subject of affinities and of structure in relation to habits. I 

 can hardly analyse the facts on which I have come to this 

 conclusion ; but I can illustrate it. Pallas's account would 

 lead any one to suppose that the Siberian strata, with the 

 frozen carcasses, had been quickly deposited, and hence that 

 the embedded animals had lived in the neighbourhood ; but 

 our zoological knowledge of thirty years ago led every one 

 falsely to reject this conclusion. 



