8i6 THE POPULAR SCIENCE MONTHLY. 



ON NEW ENGLAND AND THE UPPER MISSISSIPPI 

 BASIN IN THE GLACIAL PERIOD.* 



By Prof. JAMES D. DANA. 



SINCE the publication, in this Journal, of Prof. G. F. Wright's 

 paper on the Unity of the Glacial Epoch, nearly a year 

 since,t this subject has been much discussed in the scientific 

 journals of the country, and with some interesting developments 

 besides those within the purpose of the writers. 



1. It has been shown that there are good working geologists 

 on each side of the question. 



2. It has been made manifest that the advocates of unity are 

 mainly the geologists that have investigated Eastern glacial 

 regions in the country, and especially New England, while the 

 advocates of two Glacial epochs are chiefly those whose glacial 

 studies have been in more western regions. 



The writer, who has thus far taken no part in the recent dis- 

 cussion, here states that he has found in his geological explora- 

 tions, which have been extensive over New England, the State of 

 Maine excepted, no facts that require for their explanation an 

 appeal to two Glacial epochs, and none that has even suggested 

 the idea. 



3. The presentation of arguments on the side of unity has 

 been moderate in tone and free from dogmatism. Among geolo- 

 gists on the other side, great confidence in the obvious facts has 

 given occasion to expressions almost of accomplished triumph for 

 the two-epoch theory. 



4. Among the prominent glacial investigators, one has been on 

 both sides of the question. Having studied glacial phenomena 

 long and faithfully in New England, Warren Upham explained 

 the facts which he had observed on the theory of one advancing 

 and retreating glacier, and found evidence of its terminal moraine 

 and another halt moraine in the islands south of New England 

 and on part of the adjoining mainland. But after some years of 

 study in Minnesota and the neighboring States and over the region 

 northward through Manitoba, he adopted the theory of two 

 Glacial epochs. Returning again to New England and revising 

 the facts there presented, he was led back to his former opinion, 

 as he has announced in his recent papers. Since no geologist in 

 America is better acquainted with the facts on the two sides, or 

 more faitliful and earnest in glacial investigation, these changes 

 in his conclusions have special interest. 



* From the American Journal of Science, vol. xlvi, November, 1893. 

 f Vol. xliv, p. 351. 



