396 



SCIENCE 



[N. S. Vol. XXV. No. 636 



viously deformed and folded mountain sys- 

 tem; and that their present attitude and dis- 

 section are due to Tertiary faulting and ver- 

 tical displacement, the surface margins and 

 slope of the faulted blocks being indifferent to 

 the general geological structure of the region. 

 As to the altitude of these surfaces of 

 degradation before their sub-recent displace- 

 ment, several opinions are held. Friederich- 

 sen suggests that they originated in interior 

 basins, unrelated to the general baselevel of 

 the ocean, and hence that their present alti- 

 tude need not differ so very greatly from the 

 altitude in v?hich they were degraded (Pet. 

 Mitt., I., 1904, 272-273). Keidel explicitly 

 states that it is as yet undetermined whether 

 the present relief of the highland is due to 

 elevation of the degraded masses or to sinking 

 of the surrounding region. The undersigned 

 has expressed the opinion that the even sur- 

 faces of degradation are uplifted members of 

 a once far-extending peneplain, which bore 

 residual mountains and mountain groups here 

 and there; the best-finished part of the pene- 

 plain being seen still in or near its attitude 

 of degradation in the neighborhood of Semi- 

 palatinsk, while other parts farther south have 

 been faulted, uplifted and tilted in blocks of 

 various areas, altitudes and attitudes (' The 

 Bearing of Physiography upon Suess's The- 

 ories,' Amer. Journ. Sci., XIX., 1905, 265- 

 273). Hence, according to the second and 

 third of these views, it would appear that the 

 Tian Shan, like various other mountains, 

 must be withdrawn from the class of forms 

 whose present altitude, in relation to their 

 surroundings, is due to crustal compression. 

 W. M. D. 



THE SYSTEMATIC STUDY OF MOUNTAINS 



The systematic study of mountain forms in 

 accordance with the scheme of the physio- 

 graphic cycle has presented difficulties, be- 

 cause it has so seldom been possible to recon- 

 struct with any fair degree of success the 

 forms initiated by deformation, on which the 

 sequential forms are then to be developed in 

 due order by the processes of erosion. Sub- 

 stantial relief from this difficulty is promised 



in all those cases, now increasing in number 

 yearly, in which mountains are shown to be 

 not in the original cycle initiated by disorder- 

 ly compression and folding, but in a later 

 cycle, initiated by uplift or by relatively 

 simple block faulting, after more or less ad- 

 vanced peneplanation in a previous cycle. 

 The systematic treatment of such mountains 

 is relatively easy ; for if they are not too much 

 dissected the essential features of their initial 

 forms may be easily determined and appre- 

 hended; and their sequential forms are in the 

 main equally within the reach of explanatory 

 description. If to this be added the recent 

 increase in the understanding of high-moun- 

 tain sculpture by glaciers, first clearly gen- 

 eralized by Eichter and later presented in 

 much detail for the Alps by Penck and Briick- 

 ner, the possibility of developing a systematic 

 method of mountain description does not seem 

 so remote as it did a few years ago. 



W. M. D. 



SCIENTIFIC NOTES AND NEWS 

 Colonel W. C. Gorgas, chief sanitary officer 

 of the Isthmian Canal Commission, has been 

 appointed by President Roosevelt a member 

 of the commission. 



Peofessoe Simon Newcomb has been elected 

 honorary fellow of the Physical Society of 

 London. 



The steam yacht Virginia, on which Mr. 

 Alexander Agassiz was making explorations 

 in the West Indies, struck a submerged wreck 

 on February 11, and was obliged to go to San 

 Juan under sail, where it was placed in dry 

 dock. 



Professoe T. W. Eichards, of Harvard 

 University, will sail for Germany on March 9, 

 in accordance with the arrangements for an 

 exchange of professors between Harvard Uni- 

 versity and the University of Berlin. Pro- 

 fessor Eichards will lecture on ' The Funda- 

 mental Constants of Physical Chemistry.' A 

 laboratory has been fitted up for Professor 

 Eichards by Dr. Arthur Staehler, who last 

 year worked with him at Harvard University. 



