Down, October 21st, 1879.
Although you are so kind as to tell me not to write, I must just thank you for the proofs of your paper, which has interested me greatly.
(295/1.

See "The Shell Mounds of Omori" in the "Memoirs of the Science Department of the Univ.

of Tokio," Volume I., Part I., 1879.

The ridges on Arca are mentioned at page 25.

In "Nature," April 15th, 1880, Mr.
Darwin published a letter by Mr.Morse relating to the review of the above paper, which appeared in "Nature," XXI., page 350.