Z. Hatch — Marine Terraces in S,E. Connecticut 329 



corresponding to the different sea levels shown in the Stoning- 

 ton quadrangle. 



Correlation with Other Work. 



The question arises as to how the terraces correspond to 

 those worked out in other areas, and what were the probable 

 dates of their formation. A series of terraces has been 

 described by Dr. Barrell as extending from the base of the 

 Berkshire Mountains to the sea. The lower ones he correlates 

 with terraces in Maryland. The writer agrees with Dr. Bar- 

 rell in finding terraces at 500 feet (which he calls the '^ Lafay- 

 ette or Appomatox " level), at 200 feet (or the " Sunderland " 

 level), and 80-100 feet (or " Wicomico " level). 



Dr. Barrell also records a rather obscure terrace at 340-380 

 feet elevation in western Connecticut, which probably corre- 

 sponds to the 400-foot level in the Stonington quadrangle. 

 The 300-foot terrace has not before been noted, and will be 

 called the "Pitcher Mountain Terrace" to record the name 

 of a place where it is developed (although not as well as in 

 the broader unnamed areas to the southwest). 



The Age of the Terraces. 



The geological dates at which these terraces were formed is 

 not determined. If the 500-foot terrace corresponds to the 

 Lafayette (Brandy wine) in Maryland, as Dr. Barrell suggests, 

 then the lower ones are Pleistocene. In the Westerly region 

 there seems to have been an advance of the glacier when the 

 land stood 60 to 120 feet lower than at present, and this may 

 have been just after the erosion of the 100-foot terrace. This 

 would correspond to the Pensauken of New York and I^ew 

 Jersey and the Wicomico of Maryland. In this case all the 

 terraces noted in this region are pre-Wisconsin in age.* 



Until more work has been done on the Pleistocene in this 

 region, little more can be said. The long periods represented 

 by the older drift sheets in the interior of the continent may 

 be represented in this region by marine erosion at the 200-foot, 

 300-foot and 400-foot levels. The long time necessary for 

 the accumulation of the great ice sheets, with the relative rises 

 of sea level which are presumed to have accompanied their 

 maximum extent in many parts of the northern latitudes, 

 seems amply sufiicient for the marine planation of hill tops 

 and divides seen in this quadrangle. 



That these lower terraces seem much better developed and 



* The Talbot formation at 40-60' elevation carries ice-borne bowlders and 

 probably corresponds to the Wisconsin glacial stage. See Tolchester, Md. 

 Folio U. S. Geol. Survey, 1917. 



Am. Jour. Sci.— Fourth Series, Vol. XLIV, No. 262.— October, 1917. 

 23 



