i847] COAL. 325 



thing," as old R. Brown called it), and I am delighted with 

 it ; it really is a splendid plaything. I have been in London 

 for three days, and saw many of our friends. I was ex- 

 tremely sorry to hear a not very good account of Sir William. 

 Farewell, my dear Hooker, and be a good boy, and make 

 Sigillaria a submarine sea-weed. 



Ever yours, 



C. Darwin. 



/ C Darwin to J. D. Hooker. 



Down [May 6th, 1847]. 



My dear Hooker, — You have made a savage onslaught, 

 and I must try to defend myself. But, first, let me say that 

 I never write to you except for my own good pleasure ; now 

 I fear that you answer me when busy and without inclination 

 (and I am sure I should have none if I was as busy as you). 

 Pray do not do so, and if I thought my writing entailed an 

 answer from you nolens volens, it would destroy all my pleas- 

 ure in writing. Firstly, I did not consider my letter as 

 reasoning, or even as speculation, but simply as mental rioting; 

 and as I was sending Binney's paper, I poured out to you the 

 result of reading it. Secondly, you are right, indeed, in 

 thinking me mad, if you suppose that I would class any ferns 

 as marine plants ; but surely there is a wide distinction be- 

 tween the plants found upright in the coal-beds and those 

 not upright, and which might have been drifted. Is it not 

 possible that the same circumstances which have preserved 

 the vegetation /;/ situ, should have preserved drifted plants ? 

 I know Calamites is found upright ; but I fancied its affini- 

 ties were very obscure, like Sigillaria. As for Lepidoden- 

 dron, I forgot its existence, as happens w^ien one goes riot, 

 and now know neither what it is, or whether upright. If 

 these plants, i. e. Calamites and Lepidodendron, have very 

 clear relations to terrestrial vegetables, like the ferns have, 

 and are found 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. 



