106 REGINALD A. DALY 



If, then, advance in the interpretation of the world's great ranges can 

 be really made in any one direction, such advance must be welcomed 

 as a step toward the distant, ultimate goal of complete knowledge 

 of the earth. Not only for the sake of the single study itself, but 

 perhaps still more for the sake of putting no obstacle in the way of 

 related interpretations, it is well that close scrutiny be fixed on 

 every such subordinate theory. No further reason is necessary for 

 additional field-work on a problem now in discussion concerning the 

 physiography of mountains, namely, the meaning of the generally 

 observed accordance of levels among the higher summits of an alpine 

 range. 



The word "accordance" is used advisedly. "Equality" of 

 heights is not meant by those observers who have given the question 

 the best attention. For limited areas " subequality " of the summits 

 is a fact, but over wider stretches, and especially over the whole of 

 a single range, even subequality fails, and the accordance takes the 

 form of sympathy among the peaks whose tops in companies or in 

 battalions rise or fall together in imaginary surfaces often far removed 

 from the spheroidal curve of the earth. In general, the imaginary 

 surface which will include the higher summits of peaks and ridges 

 in an alpine range has the form of a low arch, highest in the interior 

 of the range and elongated in the direction of the main structural 

 axis of the range. Subordinate, but usual and systematic, com- 

 plications in the form of this imaginary surface are found in trans- 

 verse crenulations which alternately depress and raise the surface 

 from its average out-sloping position on the margin of the great 

 arch. The axes of these transverse depressions are often suspiciously 

 coincident with existing drainage courses. 



There is, then, at least one orderly element in the "chaos" or 

 "tumbling sea" of mountains visible from a dominating point in 

 any one of a goodly number of alpine ranges. The accordance of 

 summit altitudes has been noted in the Alps, in parts of the Caucasus, 

 in the Pyrenees, in the Sierra Nevada of California, in the Alaskan 

 ranges, in the Canadian Selkirks and Coast Range, and in the Ameri- 

 can Cascade Range. 1 



1 In the present paper the term "alpine range" is used to signify a range possessing 

 not only the rugged, peak-and-sierra form of the Swiss Alps, but, as well, the internal 



