Writes with an important fact about the parallel roads of Glen Roy. The watershed at Makoul corresponds with the lowermost of the Glen Roy lines. Over a stretch of 20 miles from east to west the lowermost of the Glen Roy lines is near parallel with the present sea level.

TFJ returns CD’s "too flattering" letter concerning Glen Roy [see 3761]. Further discussion of [A. C.] Ramsay’s, [J. D.] Hooker’s, and CL’s arguments about the formation of glacial lakes.