124 



SCIENCE. 



[N. S. Vol. VII. No. 161. 



idea of a local, and, eventually, a national 

 work for the benefit of the whole commu- 

 nity. Mr. Gano retained to the last bis posi- 

 tion as a delegate from Cincinnati to the 

 annual meeting, at Washington, of the Na- 

 tional Board of Trade, and it is but a few 

 weeks since he was here to congratulate us 

 on the extended usefulness of the Weather 

 Bureau. 



Cleveland Abbe. 

 Washington, January 17, 1898. 



CURRENT NOTES ON PHYSIOGRAPHY. 

 transverse alpine valleys. 

 E. Hitter, of Geneva, assistant on the 

 Geological Survey of France and author of 

 special studies on the region of Mt. Blanc, 

 presents the results of his researches on the 

 origin of the location of water- courses, with 

 special reference to the transverse rivers of 

 the western Alps (Le Globe (Geneva), 

 XXXVI., 1897). He discards the theory 

 of an origin along faults, as advocated bj^ 

 Daubree on the basis of experiments but 

 without local confirmation, and announces 

 a close relation between the transverse val- 

 leys and a number of ' orthogonal synclines ' 

 or transverse sags in the axes of the folds 

 into which the strata of the region have 

 been compressed. The depression of the 

 sags amounts to 1,000 meters in some in- 

 stances, as determined by measures of the 

 altitudes of geological horizons. The Arc, 

 Isere, Arve and Rhone are said by Ritter to 

 be examples of transverse rivers thus lo- 

 cated ; these rivers would, therefore, be 

 classed as transverse consequents. They 

 gather many longitudinal branches from 

 within the mountains, some of these being 

 on synclines (longitudinal consequents), 

 some on monoclines (longitudinal subse- 

 quents), and some on anticlines. For the 

 latter it is suggested that a shallow syncline 

 on the crest of the anticline may have 

 served as of temporary guide, the stream 

 having now cut down so deep that nothing 



but anticlinal structure is visible. Such an 

 explanation hardly recognizes the general- 

 ity of the problems involved. A river thus 

 perched on an arch would soon be cut to 

 pieces by the branches of its neighbors in 

 the troughs, unless the core of the arch 

 were weak enough to allow it to cut down 

 its valley very rapidly ; and in the latter 

 case a valley would be spontaneously de- 

 veloped along the axis of the arch even if 

 no shallow syncline had ever been formed 

 on its crest. The anticlinal streams are, 

 therefore, probably longitudinal subse- 

 quents, and the drainage as a whole is 

 partly consequent upon surface deforma- 

 tion, partly adjusted to the internal struc- 

 ture. 



PHYSICAL geography OF NEW YORK. 



The second article under this heading, by 

 R. S. Tarr, discusses the mountains of the 

 State (Ball. Amer. Geogr. Soc, XXIX., 

 1897, 16-40), and brings clearly to light 

 the strong contrasts of the several moun- 

 tain groups there included. Especial atten- 

 tion is given to geological structure as af- 

 fording explanation for differences of form, 

 as such as prevail between the even -topped 

 Highlands, the massive Adirondacks, the 

 linear Alleghenies and the benched Cats- 

 kills. It is to be feared that, from brevity 

 of form, misapprehension may follow from 

 the statement that, while the Himalayas 

 and Alps are like the Appalachians in 

 origin and rock structure, they are 'not suffi- 

 ciently mature' to be like them in form ; 

 but ' given time, they will become so.' The 

 reader can hardly avoid inferring from this 

 statement that the simple continuation of 

 destructive processes will, in time, trans- 

 form the other mountain ranges into an Ap- 

 palachian topography. Only by re-read- 

 ing other parts of the article can it be 

 understood that the Alps and Himalayas 

 must pass to old age and then by elevation 

 (and not by time alone) enter a new cycle) 



