With respect to the word "sterile" as used for male or polleniferous flowers, it has always offended my ears dreadfully; on the same principle that it would to hear a potent stallion, ram or bull called sterile, because they did not bear, as well as beget, young. With respect to your geological-map suggestion, I wish with all my heart I could follow it; but just reflect on the number of measurements requisite; why, at present it could not be done even in England, even with the assumption of the land having simply risen any exact number of feet. But subsidence in most cases has hopelessly complexed the problem: see what Jordanhill-Smith (16/2. James Smith, of Jordan Hill, author of a paper "On the Geology of Gibraltar" ("Quart. Journ. Geol. Soc." Volume II., page 41, 1846).) says of the dance up and down, many times, which Gibraltar has had all within the recent period. Such maps as Lyell (16/3. "Principles of Geology," 1875, Volume I., Plate I, page 254.) has published of sea and land at the beginning of the Tertiary period must be excessively inaccurate: it assumes that every part on which Tertiary beds have not been deposited, must have then been dry land,--a most doubtful assumption. I have been amused by Chambers v. Hooker on the K. Cabbage. I see in the "Explanations" (the spirit of which, though not the facts, ought to shame Sedgwick) that "Vestiges" considers all land-animals and plants to have passed from marine forms; so Chambers is quite in accordance. Did you hear Forbes, when here, giving the rather curious evidence (from a similarity in error) that Chambers must be the author of the "Vestiges": your case strikes me as some confirmation. I have written an unreasonably long and dull letter, so farewell. (16/4. "Explanations: A Sequel to the Vestiges of the Natural History of Creation" was published in 1845, after the appearance of the fourth edition of the "Vestiges," by way of reply to the criticisms on the original book. The "K. cabbage" referred to at the beginning of the paragraph is Pringlea antiscorbutica," the "Kerguelen Cabbage" described by Sir J.D. Hooker in his "Flora Antarctica." What Chambers wrote on this subject we have not discovered. The mention of Sedgwick is a reference to his severe review of the "Vestiges" in the "Edinburgh Review," 1845, volume 82, page 1. Darwin described it as savouring "of the dogmatism of the pulpit" ("Life and Letters," I., page 344). Mr. Ireland's edition of the "Vestiges" (1844), in which Robert Chambers was first authentically announced as the author, contains (page xxix) an extract from a letter written by Chambers in 1860, in which the following passage occurs, "The April number of the 'Edinburgh Review"' (1860) makes all but a direct amende for the abuse it poured upon my work a number of years ago." This is the well-known review by Owen, to which references occur in the "Life and Letters," II., page 300. The amende to the "Vestiges" is not so full