AMERICAN GLACIAL DEPOSITS. Qo 
writer to indicate a judgment respecting the specific value of the 
several formations, either in terms of taxonomy or chronology. 
It has been thought, however, that it would promote a mutual 
understanding of the formations of Europe and America if some 
approximate equivalence could be shown between the two 
unquestionably complex series. It will perhaps promote the 
differentiation of the two series to institute mutual comparisons, 
and it may facilitate a final judgment of the value of these sub- 
divisions if we are able to compare, formation by formation, the 
distant series with that which falls within our own field of 
investigation. 
T. C. CHAMBERLIN. 
