84 J. D. Dana on the origin of some of the 



three layers (M) which are of clayey sand. A B is the plane of sepa- 

 ration between this part and the layers of whitish sand. The latter 



differ not only in their white color, but also in the absence of all peb- 

 bles, and in the much greater fineness of the sands. Through the 

 washing of the waters against the shores, they were not only ground 

 up, but they also lost almost entirely the oxyd of iron that tinges the 

 quartz grains of the proper terrace formation. At the foot of the 

 slope A B there is a collection of pebbles or stones, and for a short 

 distance east of B, reddish sands ; the pebbles and sand evidently fell 

 down the bank from the layers above, when it existed as an exposed 

 slope before the beds of whitish sand were deposited. These sands, 

 moreover, were laid down in even layers, free from the oblique lami- 

 nation that occurs in the terrace formation. 



3. Mudformations in the Quinnipiac harbor. — Besides these shore 

 formations, the old harbor had its mud beds. They are the clay beds 

 situated along the borders of the present river flats or meadows imder 

 3 or 4 feet or less of sand : in these later times they have become the 

 sites of numerous brick-yards. The clay beds vary in depth from 6 

 or 8 feet to over 25, the bottom in some places not having been reach- 

 ed at the latter level. Where penetrated they are found to rest on 

 sand. The clay is very thinly and evenly laminated. The beds have 

 been opened at several points near the outer borders of the meadows, 

 on both their eastern and western sides, through a length on each of 

 about three miles. The width of the border of clay is reported 

 to be from 100 yards to a third of a mile. The two ranges 

 converge toward North Haven, where the harbor had its head, 

 and where, moreovei', the terrace formation becomes wider and crowds 

 upon the river. The clay continues north, between layers of sand, 

 under the lower part of the village of North Haven. I leai'n from 

 Mr. D. H. Pierpont, that in digging a well in the village of North 

 Haven, after passing through 7^ feet of sand, a bed of clay 4 feet 

 thick was met with, the bottom of which was ^\ feet above the level 



