[1] Scoresby's Arctic Regions, vol. i. p. 122.
[2] I have heard it remarked in Shropshire that the water, when
the Severn is flooded from long-continued rain, is much more
turbid than when it proceeds from the snow melting in the Welsh
mountains. D'Orbigny (tom. i. p. 184), in explaining the cause
of the various colours of the rivers in South America, remarks
that those with blue or clear water have there source in the
Cordillera, where the snow melts.
[3] Dr. Gillies in Journ. of Nat. and Geograph. Science, Aug.,
1830. This author gives the heights of the Passes.
[4] This structure in frozen snow was long since observed by
Scoresby in the icebergs near Spitzbergen, and, lately, with
more care, by Colonel Jackson (Journ. of Geograph. Soc., vol. v.
p. 12) on the Neva. Mr. Lyell (Principles, vol. iv. p. 360) has
compared the fissures by which the columnar structure seems to
be determined, to the joints that traverse nearly all rocks, but
which are best seen in the non-stratified masses. I may observe,
that in the case of the frozen snow, the columnar structure must
be owing to a "metamorphic" action, and not to a process during
deposition.
