Consequences of the Glacial flood. 117 
plete control in the deposition. The direction of dip in the 
¢cross-bedding is the reverse of that in the finer and redder beds 
of the lower 25 feet, and the transition is an abrupt one.* 
Only this earlier portion, made before the waters were above 
half flood height, was stratified by the Quinnipiac current. 
The torrential character of Mill River in the Whitney- 
ville gap is attested to by a number of large pot holes made in 
the sandstone of the west bank near the flood-level of the era. 
One of these pot-holes (44 feet wide and 7 deep) may now be 
seen by the road side, 140 yards above the dam and nearly 60 
feet above tide level ; and two others were opened to view and 
cut away in the grading of the road a few years since. eee 
Mill River, therefore, was the chief source of the stratified 
drift or terrace deposits of the New Haven region. e have, 
consequently, to look to it for an explanation of the more 
prominent features of the New Haven plain. 
The general southward slope of the terrace-formation from 
Mt. Carmel to the Sound has been already given. The facts 
are still better before the reader on the maps accompanying 
this paper, the height being stated on the larger map, in figures. 
A review of them in this place is therefore not necessary. 
3. The depressions of the New Haven plain. 
The depressions of the plain are: 
_, (1.) The flood-made river-channels, bounded for the most part 
by the terrace-fronts facing the existing streams. 
ie -) Depressions in the plain made by drainage from its sur- 
face 
(3.) The area of a low terrace, of 20 to 25 feet elevation, 
bordering the bay on the north side, and Mill River on the 
West and less widely on the east. me , 
(4) Two long depressions that look like portions of large 
river-channel 
(5.) The “ Kettle-holes,” 
(1.) The flood-made river-channels.—These broad river-ways of 
the flood era answer to the channels of the modern stream be- 
tween the terrace-fronts—the banks as they are ealled—of its 
modern flood-ground, and had, as I have elsewhere explained, 
the same mode of origin. Like them: (1) they were made 
along the course of the greatest velocity in flood-time; (2) 
their depth below flood-height is (excluding some later erosion 
at bottom) the depth of scour, which depth was dependent 
mainly on the velocity and the kind of bottom; and (3) ot 
* See ) ; L ii, 1870, and 
tue Jura, vo pI ners fe nto of te formalin sowNE the 
versed dip is introduced 
. 
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