My dear G.
Your letter has told us a lot of interesting news.— I am extremely glad that your work is coming to a satisfactory end. Its value I expect under a geological point of view is mainly negative, as Geologists require a much greater change of climate within a rather recent period.— There were Luxuriant forests in Spitbergen during the middle Tertiary period.2
There is a map in Wallace’s new book on Geographical Distribution, showing depth of sea according to all recent data & a calculation of its average depth viz 12,000 ft.— Humboldt estimated average height of land at 1000 ft. See p. 36 & 37 of this book.—3 I think the most interesting & probable supposition wd. be to submerge in the N. or hemisphere taking St George’s Channel4 as centre of subsidence to depth of 12000 ft, & raise at the antipodes or of hemisphere (where ever there is water) to height of 1000 ft & see the result.— There is reason to suspect that there has been great & recent subsidence in Antarctic region & near N. Zealand.—5
I hardly dare venture to hope that your astronomical problem about obliquity &c will really work.6
Your affect. | C. Darwin
Frank has made a really fine zoological discovery.—7
Please cite as “DCP-LETT-10528,” in Ɛpsilon: The Charles Darwin Collection accessed on