page 129.)

Sorby read a paper to the Brit. Assoc., and he comes to the conclusion that
gneiss, etc., may be metamorphosed cleavage or strata; and I think he
admits much chemical segregation along the planes of division. (543/2.
"On the Microscopical Structure of Mica-schist:" "Brit. Ass. Rep." 1856,
page 78. See also Letters 540-542.) I quite subscribe to this view, and
should have been sorry to have been so utterly wrong, as I should have been
if foliation was identical with stratification.

I have been nowhere and seen no one, and really have no news of any kind to
tell you. I have been working away as usual, floating plants in salt water
inter alia, and confound them, they all sink pretty soon, but at very
different rates. Working hard at pigeons, etc., etc. By the way, I have
been astonished at the differences in the skeletons of domestic rabbits. I
showed some of the points to Waterhouse, and asked him whether he could
pretend that they were not as great as between species, and he answered,
"They are a great deal more." How very odd that no zoologist should ever
have thought it worth while to look to the real structure of varieties...


2.IX.VI. AGE OF THE WORLD, 1868-1877.


LETTER 544. TO J. CROLL.
Down, September 19th, 1868.

I hope that you will allow me to thank you for sending me your papers in
the "Phil. Magazine." (544/1. Croll published several papers in the
"Philosophical Magazine" between 1864 and the date of this letter (1868).)