Dear Ramsay

I feel so much interest on the subject of foliation & cleavage, & I was so much interested & pleased at your few remarks on the Duke of Argyle’s paper,¹ that you must let me send you a few lines. As I was compelled to leave, I do not know whether you read your own paper;² but before you do so or publish, will you oblige me by running your eye again (if ever read) over my remarks p. 162–168 in my Geological volume on S. America & especially p. 167, in which I say that as in some case the foliation supervenes on cleavage “so, perhaps, in some instances, the foliation of a rock may have been determined by the original planes of deposition or of oblique current laminæ”. It now seems you have found such instances:³ indeed I once saw one but so wretched & doubtful an example that I did not think it worth notice.

Please observe that I have shown some (probably not enough) caution in other places in speaking of foliation (as not resulting from the planes of deposition) as confined to the cases of the large areas examined by me. That foliation can supervene without preexisting cleavage or stratification, I must still think (p. 167 of my volume) from the “grain” of some certainly plutonic rocks, which are passing into gneiss.— I remember being on the point of coming to your conclusion as far as I heard it, (always perhaps giving too much importance to cleavage over stratification), when I thought of the facts of the “grain” &c in plutonic rocks.

I have fought so many battles vivâ voce, with Sir C. Lyell,⁴ that I have my pluck up on the subject, so do read over the above passages in my volume, & forgive me for troubling you.

Very sincerely your’s | Charles Darwin