326 L. Hatch — Marine Terraces in S.E. Connecticut. 



at the 400-foot level, all reach to the elevation of the broad 

 upland patches farther north ? It is just as useless to try to 

 work out any one level for the peneplain, for in that case the 

 accordance of levels above and below it must be accounted for. 

 Partial base levels are seen along the river valleys, but are as 

 hard to reduce to any one erosion surface as the tops of the 

 hills. 



The Cretaceous peneplain must have crossed the region 

 somewhere, however, if the interpretation of various workers 

 in neighboring fields is correct. The only clue to its position 

 within the quadrangle is found in a well boring on Fishers 

 Island.* Bedrock is found 280 feet below sea level and is 



Fig. 5. 





'■^^n, 



'loo y/h /ff/i 



Tishers Is. 



— S 



o 



^^^|p Aiaik, Honzonkl looj Vpfhical 



Fig. 5. Possible relations of the Cretaceous peneplain to the topography 

 of the Stonington Quadrangle. 



overlain immediately by clay similar to the Cretaceous mate- 

 rial on Long Island. If this depth may be taken as the posi- 

 tion of the peneplain at three miles from shore, it has a slope 

 of 90 feet per mile below the sea. This slope continued across 

 the Stonington quadrangle would take it far above the present 

 surface (fig. 5). The peneplain might, of course, be warped 

 to correspond to the tops of the higher hills, bnt if so it 

 changes from a slope of 90 feet per mile to one of 14 feet per 

 mile within a distance of eight miles from the coast. It could 

 not, however, be made to include the best flat areas without 

 the complex warping mentioned above. In any case, the pene- 

 plain surface is practically unrecognizable in the region, the 

 topography having been entirely recarved by subsequent ero- 

 sion. 



* Fuller, Myron L., Geology of Fishers Island, N. Y., Bull. Geol. Sec. 

 Amer., vol. xvi, pp. 367-390, 1905. 



