I think you ought to allude to Alph. De Candolle's great book, for though it (like almost everything else) is washed out of my mind, yet I remember most distinctly thinking it a very valuable work. Anyhow, you might allude to his excellent account of the history of all cultivated plants.
How shall you manage to allude to your New Zealand and Tierra del Fuego work? if you do not allude to them you will be scandalously unjust.
The many Angiosperm plants in the Cretacean beds of the United States (and as far as I can judge the age of these beds has been fairly well made out)seems to me a fact of very great importance, so is their relation to the existing flora of the United States under an Evolutionary point of view.
Have not some Australian extinct forms been lately found in Australia? or have I dreamed it?
Again, the recent discovery of plants rather low down in our Silurian beds is very important.
Nothing is more extraordinary in the history of the Vegetable Kingdom, as it seems to me, than the APPARENTLY very sudden or abrupt development of the higher plants. I have sometimes speculated whether there did not exist somewhere during long ages an extremely isolated continent, perhaps near the South Pole.
Hence I was greatly interested by a view which Saporta propounded to me, a few years ago, at great length in MS. and which I fancy he has since published, as I urged him to do--viz., that as soon as flower-frequenting insects were developed, during the latter part of the secondary period, an enormous impulse was given to the development of the higher plants by cross-fertilization being thus suddenly formed.
A few years ago I was much struck with Axel Blytt's Essay showing from observation, on the peat beds in Scandinavia, that there had apparently been long periods with more rain and other with less rain (perhaps connected with Croll's recurrent astronomical periods), and that these periods had largely determined the present distribution of the plants of Norway and Sweden. This seemed to me, a very important essay.
I have just read over my remarks and I fear that they will not be of the slightest use to you.
I cannot but think that you have got through the hardest, or at least the most difficult, part of your work in having made so good and striking a sketch of what you intend to say; but I can quite understand how you must groan over the great necessary labour.
I most heartily sympathise with you on the successes of B. and R.: as years advance what happens to oneself becomes of very little consequence, in comparison with the careers of our children.
Keep your spirits up, for I am convinced that you will make an excellent address.
Ever yours, affectionately, CHARLES DARWIN.
[In September he wrote:--"I have this minute finished reading your splendid but too short address.
I cannot doubt that it will have been fully appreciated by the Geographers of York; if not, they are asses and fools."]
CHARLES DARWIN TO JOHN LUBBOCK.
Sunday evening [1881].
My dear L., Your address (Presidential Address at the York meeting of the British Association.) has made me think over what have been the great steps in Geology during the last fifty years, and there can be no harm in telling you my impression. But it is very odd that I cannot remember what you have said on Geology. I suppose that the classification of the Silurian and Cambrian formations must be considered the greatest or most important step;for I well remember when all these older rocks were called grau-wacke, and nobody dreamed of classing them; and now we have three azoic formations pretty well made out beneath the Cambrian! But the most striking step has been the discovery of the Glacial period: you are too young to remember the prodigious effect this produced about the year 1840 (?) on all our minds. Elie de Beaumont never believed in it to the day of his death! the study of the glacial deposits led to the study of the superficial drift, which was formerly NEVER STUDIED and called Diluvium, as I well remember.
The study under the microscope of rock-sections is another not inconsiderable step. So again the ****** out of cleavage and the foliation of the metamorphic rocks. But I will not run on, having now eased my mind.
Pray do not waste even one minute in acknowledging my horrid scrawls.
Ever yours, CH. DARWIN.