Dear Sir

It is such a very long time since I had no news from You, that I improve the occasion of sending You my memoir which You have kindly allowed to be inscribed to You, by asking some news about Your health.— The first part of my paper is merely an osteological analysis with a view to descent of all fossil Ungulata, the special description of Anthracotheriae will follow shortly.—¹

The past summer and this winter I had some geological work to do, and I hope to be in the spring in England to see some of the greater chalk collections, as the chalk is the formation I am especially interested. I found in the South of France, near Mondragon a large (300 feet thick) freshwater deposit of the age of your upper greensand, as it is laying on the Gault and covered by banks of Ostea columba;² there are large Cyrenas, Melaniae and even Ampullariae in the lignites which accompany this freshwater formation.—³ There was a subsidence afterwards which continued till the time of Your “lower chalk without flints” and then a new reelevation of land and freshwater deposits going on through all the time of the upper chalk,— this upper chalk freshwater formation is covered near Barcelona by a marine band with Hippurites Leymeryii⁴ corresponding to the Mastricht uppermost chalk.—⁵ In this way You see that we have a good bit of the freshwater conditions of the cretaceous period, and the comparison of the Mollusca with those of the Wealden⁶ is attended with much interest. The lower beds (parall. greensand) are not known at all, but the upper freshwater chalk consist of the Strata which Lyell and Murchison have mentioned near Aix, deeming them tertiary, while now they are found covered by a band of Hippurite Limestone on their cretaceous age is undoubtedly sure.⁷

I hope to once more to the locality and to publish something on the subject.—⁸ How are Your projected books going on, I think you were occupied during my stay in England with Fertilisation of Plants, may I ask is anything to be published shortly and in this case please to remember me as Your translator.—⁹ The book about Expression is already sold in nearly 2000 copies, so that the costs are nearly entirely paid and I hope to send You in six months Your share in the edition. (Our accounts with the bookseller are made every half year).—¹⁰

My wife is also very well and presents her compliments, she is hardly working at something very intricate about the stability of Saturn rings, but the matter seems to be so difficult that we dont clearly see when there will be an ⁠⟨⁠end⁠⟩⁠ of it.¹¹ Clark Maxwell wrote an elaborate memoir on the same subject in 1859, but we could not, even at the Oservatory of Berlin get it here, and I am going to ask Murray to hunt me up a copy in England.¹²

I hope all Your family is going well, and beg You to present our compliments to M^rs and Miss Darwin¹³

Your very truly | W. Kowalevsky