128 J. D. Dana— Phenomena of the Champlain Period. 
Note on the Glacial flood of the Connecticut River Valley. 
the e xplanations given in my paper on the ne val- 
have been imperfectly understood, I add 1 a few 
words on the subject. Professor C. H. Hit cheock, in 8 paper a 
before the American Adeosittics in 1882 (Proc. Am. Assoe., p. 
825), og accepting the — adopted by Mr. Warren 
U ween ‘ delta-terraces” and “ highest normal terraces,” 
and abjectag to taking the aecalied . dextect aces” as the nor- 
mal highest, as done for many localities by me, remarks that “if 
e are not required to accept the deltas as a measuring rod, we 
shall greatly reduce the depth of the stream and thas learn why 
the velocity as calculated by Dana was far too grea 
No calculations of the velocity corresponding S ‘the reduced 
depth are given. 
Tn my paper I state that one pr ominent ssl before me in my 
- whe 
much delta oe as those ‘iad dus the progress of the 
ing t 
ee flood; and yet they rise bn little, where at all, above the 
flood plain of the main stream, and have no claim to so ’ distinctive 
a name, 
Again, if the level of the “ highest normal terraces” of Upham 
are taken as marking flood-level, they indicate an impossible water 
surface for the river, since the heights given vary greatly in a few 
miles 
24 miles farther south, at North Thetford, the waaet is 146 feet; 
and farther south, 170 to 180 feet for many miles. (The “ De Ita- 
terraces” are in part still higher). 
us, within 83 miles, the followin carb in the level of 
CEOS Siar 
_ flood waters are indicated, if we take Mr. Upham’s “ highest ae oe, 
how: 
mal terraces” as showing the water eiik: 166, 118, 80, 60 4 
* This Journal, xxii, 451, 1881, xxiii, 87, 179, 360, xxiv, 98, 1882. 
