114 J. D. Dana—Phenomena of the Champlain Period. 
the map are above mean tide, which is 3 feet below mean high — 
tide. The map (Plate II) gives the original square of the city, 
half a mile each way, as laid i 
over the whole breadth of the map. 
Before describing the ‘“ Kettle-holes” of the plain and the 
valley-like depressions that look like deserted river channels, 
it is necessary, preparatory to a discussion of their origin, to 
review briefly the facts relating to the transporting agents of 
the region, although the facts are contained, for the most part, 
in former papers by the author. 
I shall treat first, of the rivers; secondly, of the deposits 
made by the flooded rivers; thirdly, of the depressions over the 
flood-plain or terrace-formation. 
1. The Rivers. 
The order of size in the three streams which traverse the 
New Haven Region on their way to the Sound, is now as 
follows: 
Length. Approximate drainage-area. 
120 sq. m. 
1. Quinnipiac River 33 miles 
2, Mill River ee 1G 66-28% 
3. West River se el 
out in 1638; the city now extends — 
In the era of maximum flood the relative rank of the first 
two rivers was reversed, through a gain in length, on the part 
of Mill River, of 15 miles from the Quinnipiac, the upper balf, 
and also the larger part of Farmington River. (This Journal, — 
xxv, 441, 1883). The size of the three streams thus became— 
Length. Drainage-area. 
Ly amine Ser 18 m. 65 sq. m. 
2. Mill River _ 7 4602 °*. 
3. West River 162 Seay 
The first two of these streams were changed by the flood 
lines on trap ridges extending higher. West River flowed, a8 — 
Fy 
Sess teers SER are 
Way ane Sine eee ee Se eee 
tp oe eee te ee es ee | 
Seesciest 
