I do not quite agree with your estimate of Richardson's merits. Do, I beg you (whenever you quietly see), talk with Lyell on Prestwich: if he agrees with Hopkins, I am silenced; but as yet I must look at the correlation of the Tertiaries as one of the highest and most frightfully difficult tasks a man could set himself, and excellent work, as I believe, P. has done. (564/2. Prof. Prestwich had published numerous papers dealing with Tertiary Geology before 1857. The contributions referred to are probably those "On the Correlation of the Lower Tertiaries of England with those of France and Belgium," "Quart. Journ. Geol. Soc." Volume X., 1854, page 454; and "On the Correlation of the Middle Eocene Tertiaries of England, France, and Belgium," ibid., XII., 1856, page 390.) I confess I do not value Hopkins' opinion on such a point. I confess I have never thought, as you show ought to be done, on the future. I quite agree, under all circumstances, with the propriety of Lindley. How strange no new geologists are coming forward! Are there not lots of good young chemists and astronomers or physicists? Fitton is the only old geologist left who has done good work, except Sedgwick. Have you thought of him? He would be a brilliant companion for Lindley. Only it would never do to give Lyell a Copley and Sedgwick a Royal in the same year. It seems wrong that there should be three Natural Science medals in the same year. Lindley, Sedgwick, and Bunsen sounds well, and Lyell next year for the Copley. (564/3. In 1857 a Royal medal was awarded to John Lindley; Lyell received the Copley in 1858, and Bunsen in 1860.) You will see that I am speculating as a mere idle amateur. LETTER 565. TO S.P. WOODWARD. Down, May 27th [1856]. I am very much obliged to you for having taken the trouble to answer my query so fully. I can now be at rest, for from what you say and from what little I remember Forbes said, my point is unanswerable. The case of Terebratula is to the point as far as it goes, and is negative. I have already attempted to get a solution through geographical distribution by Dr. Hooker's means, and he finds that the same genera which have very variable species in Europe have other very variable species elsewhere. This seems the general rule, but with some few exceptions. I see from the several reasons which you assign, that there is no hope of comparing the same genus at two different periods, and seeing whether the tendency to vary is greater at one period in such genus than at another period. The variability of certain genera or groups of species strikes me as a very odd fact. (565/1. The late Dr. Neumayr has dealt, to some extent, with this subject in "Die Stamme des Thierreichs," Volume I., Wien, 1889.)