Topographical Features of the Neio Haven region. 87 



with regard to its species cannot be verified. It is also stated by Mr. 

 Stiles that impressions of leaves liave been found in the clay. The 

 muck at a depth of 6 to 12 feet has been found to contain at places 

 great logs and stumps, nuts and leaves, accredited popularly (and 

 probably rightly) to trees of existing species. But these are subse-- 

 quent in age ; for the muck beds of the interior of the basin could 

 not have been begun until the salt-water harbor had been mostly ob- 

 literated by an elevation of the land. 



The above is all we have yet gathered from the deposits of the 

 New Haven region with regard to the life of this era. It is certain 

 that there is much more to be learned ; for there is good evidence of 

 the existence of the ^lastodon formerly in this part of Connecticut. 

 While digging for the Farmingtou Canal in Cheshire, 13 miles north 

 of New Haven, three or four teeth of a Mastodon were found, (Am. 

 J. Sci., xiv, 187, 1828); and long before, remains of the same animal 

 were obtained near Sharon. xVIso later, a vertebra of a Mastodon was 

 brought to light in digging a canal for a manufactory in Berlin, the 

 bone occurring in "a tufaceous lacustrine formation, containing 

 bleached fresh-water sliells of Planorhis, Lymncea, Cyclas, etc., sim- 

 ilar to those of the waters in the vicinity." (Am. J. Sci., xxvii, 165, 

 1835). This Berlin Mastodon existed as late as the Champlain era ; 

 for if of earlier time the lacustrine deposit would have been buried 

 beneath drift, either the stratified or unstratified. 



6. Terrace or Recent Era. 



The work of the waves, tides and rivers went forward until the 

 great drift formation of the bay and river valleys was completed. 

 An elevation of the land then commenced which affected cotempora- 

 neously all New England, and, it is believed, a large part of the con- 

 tinent, and bordered the rivers and lakes with terraces. This eleva- 

 tion marks the transition to the Terrace or Recent era. 



1. Amount of Elevation. 



In determining the amount of elevation of the land about the New 

 Haven region, we have to take it for granted, not only that the plain 

 was leveled off by the waters, but further, that a considerable part of 

 its surface at the time nearly coincided with that of the water. The 

 even character of the plain shows that this is not an improbable as- 

 sumption. 



The following are the results of the observations upon its level thus 

 far made. The heights along the river valleys, the Beaver Pond ba- 



