L. Ilatoh — Marine Terraces in S.E. ConnectioiU. 319 



Art. XXVII. — Marine Terraces in Southeastern Con- 

 necticut '^"^ by Ladea Hatch. 



Introduction, 



In mapping the geology of the Stonington quadrangle, 

 Connecticut, the writer has been interested in testing the con- 

 trasting hypotheses used in interpreting the accordance of 

 summit levels in Southern j!^ew England. The problem is 

 particularly important for the physiographer, because of the 

 attribution of wave erosion to areas believed by many to be 

 type examples of subaerial peneplanation. 



Topography of the Stonington Quadrangle. 



The topography of the Stonington quadrangle consists of 

 two strongly contrasting types. One is found in the narrow 

 belt of rough land which extends eastward along the coast 

 from Watch Hill, R. 1., and which is continued toward the 

 west in Fishers Island. Within this belt rock outcrops are 

 practically absent, and the knob-like hills, irregular ridges 

 and undrained depressions show a well-developed terminal 

 moraine. f North of the belt of terminal moraine, the topog- 

 raphy is controlled chiefly by rock hills which increase in 

 height toward the northwest. Many of the hills are isolated, 

 but in places merge for five or six miles so as to form an. 

 almost continuous upland between drainage lines. Many of 

 the hills are broad, most of them being a mile or more in the 

 longer dimension, and all have noticeably flat tops. 



At a distance the sky line made up of many hills shows a 

 remarkably even surface. On closer examination, however, 

 one sees that the upland level is not a general slope toward 

 the sea, nor is it a rolling topography suggestive of subaerial 

 erosion alone, but its parts really constitute a series of broad 

 low steps or terraces which have been greatly dissected by 

 stream action. 



To restore a general picture of the upland surface a system 

 of projected proflles was used. For this purpose the quad- 

 rangle was divided into strips paralleling the major river 

 valleys and averaging about 2^ miles in width. Profiles of the 

 divides between the north-south valleys, and of the tops of 

 the hills within the same strip, were projected on the same 

 paper. The results are shown in tig. 1. It will be seen at 



* Publislied by permission of the Superintendent of the Connecticut 

 Geological and Natural History Survey. 



f This moraine is a continuation of the Harbor Hill moraine on the inner 

 side of Long Island. 



