EDITORIALS. 849 



later episodes (or the earlier episodes) exclusively and those 

 who have studied both. To have studied the Hudson River beds, 

 east and west, is an inadequate preparation for deciding whether 

 they are to be placed in a separate epoch from -the Trenton beds 

 or not. Both the Hudson River beds and the Trenton beds 

 should be studied in regions where both are well displayed. So 

 of the drift deposits. Classified on the basis of the formational 

 distribution of critical studies, the true generalization falls easily 

 into form, viz., those who have studied the formations of one 

 epoch believe in one epoch ; those who have studied the forma- 

 tions of more than one epoch, believe in more than one epoch. 



The special individual opinion upon which Professor Dana 

 lays stress ceases to have significance, or rather has its signifi- 

 cance reversed, when it is observed that the studies on which it 

 is based (most admirable in extent and in quality) fall almost 

 exclusively within zones referred, by common consent, to a sin- 

 gle, late, relatively brief glacial epoch. 



Respecting the reference of the differences between the drift 

 of the east and of the west to meteorological causes there is 

 room here only for inviting attention to the pregnant fact that 

 the greatest southward extension of the drift is found where the 

 present meteorological and topographical conditions are least 

 favorable. The drift of the interior reaches south of 38 latitude, 

 that of New England only a little south of 41 , a difference that 

 equals about three-fourths of the extent of New England in lati- 

 tude, exclusive of Maine. The inferiority of the drift of New 

 England in extent, in massiveness, and in serial development is 

 the feature that calls for explanation in adverse conditions rather 

 than the magnificent deployment of the glacial series on the 

 plains of the interior. T. C. C. 



