My dear Hooker

I cannot resist thanking you for your most kind note. Pray do not think that I was annoyed by your letter: I perceived that you had been thinking with animation, & accordingly expressed yourself strongly & so I understood it.— Forefend me from a man who weighs every expression with Scotch prudence. I heartily wish you all success in your noble problem & I shall be very curious to have some talk with you & hear your ultimatum. I do really think, after Binneys pamphlet, it will be worth your while to array your facts & ideas against an aquatic origin of the coal—though I do not know whether you object to fresh-water. I am sure I have read somewhere of the cones of Lepidodendron being found round the stump of a tree; or am I confusing something else. How interesting all rooted better it seems from what you say than upright specimens become.—

I wish Ehrenberg would undertake a microscopical hunt for infusoria in the underclay & shales;¹ it might reveal something. Would a comparison of the ashes of terrestrial peat & coal give any clue: peat-ashes are good manure & coal-ashes, except mechanically, I believe are of little use: does this indicate that the soluble salts have been washed out? ie if they are not present.—

I go up to Geolog. Council today² —so farewell | Yours affectionately | C. Darwin