94 J. D. Dana—The Flood of the Connecticut River Valley 
little over site years ago),* were deposits far away from the 
region of ice; for the glacier of the Sierra Nevada, according 
to Whitney, ak also Brewer, did not reach down within 2,000 
feet of their level. Yet they have nearly identical features with 
those of the Connecticut. This is true even to the greater 
coarseness, in many parts, of the upper deposits. The route of 
the party T was with, after reaching the wally of the Upper 
Sacramento, just south of Jativade 40° 45, led us for fifteen 
terrace-plains, the terrace-front of 40° and sometimes 90° 
through ee abrasion, were peculiar only in their 
wonderful extent. 
The spaaleh of the channel-way has other determining causes 
besides velocity: such as the amount of transported material 
for deposition, and the form of the enclosing valley, as already 
explained. Along the Hudson River below the Highlands, 
the waters at the time of the great flood were 75 to 95 
feet above the present level; and yet, owing to the near- 
ness of the rocky hills, the channel-way was not a fourth 
wider than the present river; for the higher terraces rise almost 
immediately from its banks. On the other hand, the channel- 
way of the Connecticut at Hartford, Conn., had a width of 12 
miles; owing partly to the low level of the region, and largely 
to the ong trap-range on the west, shutting out tributaries and 
their contributions of sand and grave The Far mington River 
which comes from that direction through a cut in the trap- 
range, and reaches the Connecticut half a “dozen: miles north of 
Hartford, left a large part of its transported material west of 
the range in the Farmington Valley, where it made terraces 
over a hundred feet in height. 
3. Normal upper terraces. 
Professor Edward Hitchcock, finding that the terraces of the 
Connecticut about the mouths of tributaries were much the 
. ‘tesignated them, in his “Surface Geology,” “ delta- 
terraces ;” and Mr. Upham, adopting the view, represents them 
as cola above the level of the ‘‘ highest normal terraces” 
of the valley. The difference in height | between “ap Highs kinds 
of terraces, the ‘‘highest normal terraces, ” an e ‘“delta- 
terraces,’ ’ along some parts of the Connecticut, i ioe by 
Mr. Upham to be 40 to 50 and sometimes 100 fee 
* October 11, 1841, on a land Pearce from the Columbia River to San uy 
, connected w ith the U. 8. Exploring Expedition under Captain Wilkes. See 
my Geo ological Report of the Expedition, 756 pp. 4to, 1849, pp. 659-674; and for 
ap abstract, this Journal, II, vii, 257, 1849. 
