NOVEMBEK 5, 1915] 



SCIENCE 



635 



Professor Josepla Barrell, of Yale University, 

 on Friday and Saturday, October 15-16. 



The purpose of the excursion was to deter- 

 mine whether or not the so-called Cretaceous 

 peneplain of southern New England was the 

 work of subaerial or of marine erosion, and 

 was conducted by the author of the latter 

 theory. 



In the preliminary lecture delivered in Pea- 

 body Museum, Tale University, Professor Bar- 

 rell pointed out that the importance of pene- 

 planation in continental interiors was not ques- 

 tioned nor the quantitative dominance of river 

 erosion even on the eastern side of the Appa- 

 lachians. From evidence based on a broad 

 study of the country between Vermont and 

 Virginia it was concluded that the so-called 

 peneplain of southern New England was orig- 

 inally stair-like or terraced in its character, 

 the terraces facing the sea and bearing the 

 marks of having been developed by recurrent 

 marine denudation. By projecting the base of 

 the Potomac and later formations their rela- 

 tions were brought out with the marine ter- 

 races of Maryland. The oldest terrace is re- 

 garded as Upper Cretaceous. The Piedmont 

 plateau is regarded as developed by alterna- 

 tions of marine and subaerial denudation dur- 

 ing the Pliocene. 



The party left New Haven Saturday at 8 :00 

 o'clock for Waterbury, Conn., where auto- 

 mobiles awaited. The route traversed extended 

 through Morris, Litchfield and Goshen to 

 Torrington. Luncheon was eaten in Litchfield. 



The four terraces recognized in this region 

 by the leader, regarded as Pliocene in age, and 

 pointed out to the party are : 



Cornwall terrace, elevation 1,680-1,720, 

 Goshen terrace, elevation 1,340-1,380, 

 Litchfield terrace, elevation 1,100-1,140, 

 Prospect terrace, elevation 880-920. 



Of these terraces the Prospect in the local- 

 ity viewed was seen to have been much dis- 

 sected by subaerial erosion while the Litchfield 

 has a remarkably smooth surface. No line of 

 cliffs separates these two terraces, the separa- 

 tion being determined largely from topographic 

 maps by the rather rapid descent of the sur- 

 face near the junction of the two terraces. 



Eather pronounced but much dissected scarps 

 between the Litchfield and Goshen and between 

 the Goshen and Cornwall terraces were pointed 

 out. 



It was suggested by members of the party 

 that the terraces might have been caused 

 either, (1) by monoclinal warping or, (2) by 

 a difference in the hardness of the rock. It 

 was pointed out by one of the physiographers, 

 however, that mere difference in hardness of 

 rock would hardly account for the succession 

 of dissected levels which was observed. The 

 leader regarded monoclinal warping as inap- 

 plicable when applied to the actual details as 

 developed across the country. 



In general, Professor Barrell holds that the 

 highest or Cornwall terrace was first cut by 

 the marine erosion of a region of slight relief. 

 The region was then raised, perhaps 400 or 500 

 feet, the sea retreated, subaerial denudation 

 etched out the land surface, then moderate 

 submergence took place to a level about 340 

 feet below the Cornwall level and the second 

 or Goshen terrace was planed. Another oscil- 

 lation resulting in a final elevation of 240 feet 

 more permitted the sea to cut the Litchfield 

 terrace. The Prospect terrace was cut when 

 the region was raised about 220 feet further 

 and perhaps after a prolonged stage of sub- 

 aerial denudation. Lower and younger levels 

 were cut by the waves on the seaward slopes 

 before the sea reached its present position with 

 reference to the land, each phase being repre- 

 sented by subaerial denudation farther inland. 

 The sediment which had been spread over the 

 sea bottom as the land was cut away to form 

 the terraces has been removed by the streams 

 since the successive terraces were subjected to 

 subaerial erosion. 



Twelve colleges and universities were repre- 

 sented by the fifty-two persons who were on 

 the excursion. 



The beauty of the autumnal coloring and of 

 the region traversed added pleasure to one of 

 the most interesting and largely attended of 

 these annual excursions. 



H. F. Cleland, 



