TO C.LYELL.Down, Thursday, February 15th [1866].
Many thanks for Hooker's letter; it is a real pleasure to me to read his letters; they are always written with such spirit.

I quite agree that Agassiz could never mistake weathered blocks and glacial action; though the mistake has, I know, been made in two or three quarters of the world.

I have often fought with Hooker about the physicists putting their veto on the world having been cooler; it seems to me as irrational as if, when geologists first brought forward some evidence of elevation and subsidence, a former Hooker had declared that this could not possibly be admitted until geologists could explain what made the earth rise and fall.

It seems that I erred greatly about some of the plants on the Organ Mountains.

(364/1.