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



Rock and the Beaver Hills on the other, close alongside of the latter. 

 Mill River entered a narrow arm of the bay between East Rock and 

 Sachem's ridge, and the waves widened its head and battered Mill 

 Rock for some distance west of Whitneyville. This Mill River arm 

 was encumbei'ed by two or three low sandstone islands, the northern- 

 most of which is now the site of the residence of Stephen Whitney. 

 West River opened into another ai'm which lay between the eastern 

 of the Woodbridge heights (or the Edgewood range of hills) and the 

 Beaver Hills, and West Rock Cliff and Pine Rock overlooked it on 

 the north. Up the Quinnipiac valley, beyond East Rock, stretched a 

 long and broad arm of the bay, which was the great inner harbor. 



We come now to the consideration of the action of the waters of 

 the bay in arranging the material dropped into them by the melting 

 glacier. The large boulders were evidently the first to fall ; for none 

 were found on the plain when it was first taken possession of by the 

 colonists, although such masses were then very numerous over the low 

 Beaver Hills and wSachem's ridge, and are somewhat so still notwith- 

 standing man's free use of them. Furtlier, in no excavations into the 

 alluvium of the plain for cellars, wells, or other purposes, (as we are 

 informed by Messrs. Perkins & Chatfield, Mr. Isaac Thomson and Mr. 

 D. W. Buckingham, who have superintended such work for years past) 

 have boulders anywhere been found, with only two exceptions ; and 

 these are really no exceptions, since the boulders in each case lay on 

 the foot slopes of sandstone ridges. One occurred at a depth of 10 feet 

 beneath the gravel of the alluvium, and was found while making a pit 

 in Trumbull St., near the house of Prof. Fisher; it was of trap and 

 about two feet across. In the other case a number of large stones 

 were met with in digging a well on Whalley Avenue near Blake Street ; 

 Mr. Buckingham, who reported tlie fact to me, attributes their occur- 

 rence there to the nearness of the place to the Beaver Hills. 



As the melting went forward, the sand, pebbles and cobble stones 

 were thrown down together; but they underwent as they fell an aiTange" 

 raent which varied according to the movements in the waters beneath. 

 The bay had its tidal currents, as now ; its areas of comparatively 

 still waters ; and besides, certain channels along which the flow of 

 the rivers increased greatly the force of the ebbing tide. The strati- 

 fication of the deposits varied accordingly. Where the cun-ents were 

 strong, they washed away the sand from the stones, or if very strong, 

 the sand and smaller pebbles, and thus layers of coarse gravel were 

 made — gravel beds being always deposits from which the sand has 

 been sifted out by moving or flowing water. Along the main river 

 courses there ought to be found, consequently, long gravel courses^ 



