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.

Jamieson has revisited Glen Roy and confirmed his theory of glacier lakes.

A. G. More considers CD the most profound of reasoners.

Further comments on Jamieson’s theory of the formation of the roads of Glen Roy; paper by Jamieson dealing with glaciation in Scotland ["On the ice-worn rocks of Scotland", Q. J. Geol. Soc. Lond. 18 (1862): 164–84].

Comments on paper by A. C. Ramsay on the glacial formation of lakes ["On the glacial origin of certain lakes", Q. J. Geol. Soc. Lond. 18 (1862): 185–204].

Criticises remarks by John Tyndall on glacial formation of Swiss valleys.

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.