proceedings: geological society 447 



dences of the presence of platforms submerged to a great depth along 

 several of the continents — one at 3000 feet and the trace of another 

 at 6000 feet. Spencer did not believe that the phenomena in Norway- 

 justified De Geer's estimate of 10,000 years for the period which had 

 elapsed since the end of the ice-age. There has been too much subse- 

 quent erosion. From the phenomena shown at Niagara 40,000 years 

 seemed a probable estimate. 



Bailey Willis spoke of the delta plain of the Yellow River in China. 

 He did not believe that the explanation which some had advanced, 

 attributing its origin to submarine planation, was correct. He believed 

 that it has been maintained as a very fiat plain because of subsidence 

 of its inner portion, and that therefore the low gradient is to be attrib- 

 uted to warping. The delta of the Amazon likewise has a very low 

 gradient in spite of the great quantities of sediment which are being 

 deposited upon it. Here also the phenomena must be explained by 

 postulating a subsiding area. Along the Argentine coast there are 

 evidences of warping on an extensive scale. Such phenomena cause 

 a rise in one area and sinking in another, and complicate the strand- 

 line problem. 



Arthur Keith expressed his agreement with Professor Barrell in 

 considering that there are evidences of many successive terraces along 

 the Atlantic Coast, but disagreed with the view that attributed to them 

 a submarine origin. He asked for Barrell's criteria. Barrell replied 

 that the terraces along the broad river-valleys were, in his belief, sub- 

 aerial, and were to be attributed to river erosion at the periods corre- 

 sponding to stages of sea-level at which marine planation had formed 

 the platforms whose inner margins were essentially parallel to the 

 present coast-line. The evidence regarding the marine origin of the 

 latter terraces was too extensive for presentation at the moment, but 

 would appear later in published form. 



Sidney Paige inquired as to Barrell's reasons for believing that 

 along the Atlantic coast an oscillatory movement of the strand-line 

 had occurred just previous to the development of each platform. Bar- 

 rell replied that in every case the coast-line was very sinuous at the 

 time of platform development. Analysis of the features showed that 

 just prior to the long stand of the sea represented by each platform there 

 had been an elevatory movement, resulting in the carving of stream- 

 valleys, followed by a slight re-submergence, with drowning of the 

 valleys; and a long stand, resulting in the development of a submarine 

 plain. President Vaughan thought that all those who had been engaged 

 on coastal plain work would be in essential accord wdth Barrell's views. 



E. W. Shaw spoke of the evidence of movements in the southern 

 coastal plain region during Quaternary time. The effects observed 

 could not be explained by river-work, as Chamberlain and Salisbury 

 had attempted to do. President Vaughan spoke of the great impor- 

 tance of the study of the nature and character of submarine profiles 

 which Barrell had made. 



C. N. Fenner, Secretary. 



