My dear George

I am very glad indeed that you have come to such a point in your work, as to get a little rest to your mind.— I do not think any geologist w^d. be shocked at your assumption of 1 foot of elevation per century, or at your table land, as I believe the plateau of Mexico is 10,000 & a large area of Thibet fully that much.—² I do not know whether it w^d. make calculations easier, but seeing how commonly deep sea comes close up to the higher sides of continents, you might make your elevated area abruptly separated from your depressed area.— You are aware that, as Lyell has shown, the world can be divided so that almost all the land lies in one hemisphere & all the water in the other.³ I suppose the mean height of all the land might be assumed to be 1000 ft & the depth of all the ocean at 2000 fathoms. & it w^d not be difficult to estimate the difference in specific gravity of rock & water. What a curious problem (but I suppose very difficult) it w^d be to ascertain what the effect w^d. be of reversing the present positions of land & water.

I think that as in your Cousin paper,⁴ it will be of considerable importance to geologists &c & to know that the gradual elevation cannot cause any great change of climate

Ever your affect | C. Darwin

It will be very interesting to know what Adams thinks of your method.⁵