92 PROCEEDINGS OP THE WASHINGTON MEETING 



force). Yet some structures, correctly described as synclines and anticlines 

 because of their arrangement of dips, are probably due to forces acting radially 

 and not directly parallel to the earth's surface. In any case, it seems better, 

 as far as possible, to keep all these elementary terms purely empirical in 

 meaning and free from theoretical connotation. 



Summary 



Thus simplicity, the demands of a logical system, the active need of field 

 geologists, and a certain degree of priority "suggest that Button and Geikie 

 should be followed in their definition of "monocline." It may be noted that 

 de Margerie and Heim recommended the noun "monoclinal'' as a synonym for 

 the continental word "Flexur," or "flexure." ' Hence there appears to be no 

 reason why French and German writers should not aid in internationalizing 

 the nomenclature here advocated. 



If "monocline" and "monoclinal" be fixed in the Dutton-Geikie sense, the 

 broad, useful concept denoted by the "monoclinal" of W. P.. and H. P. Rogers 

 needs a new name. As already observed, that term is readily found by follow- 

 ing literally the Rogers recipe for its manufacture. They intended to name a 

 body of strata showing throughout dip in the same direction and for that 

 "homocline" (or "homoclinal" ; adjective, "homoclinal") is the appropriate 

 word. Its use would have the advantage of rescuing "monocline" from its 

 threatened fate of meaning two different things, and therefore meaning neither 

 without cumbrous explanations. In stratigraphic. physiographic, economic, 

 and even philosophical geology "homocline" should be distinctly useful. 



Presented in abstract extemporaneously. 



Discussion 



Mr. G. W. Stose : I welcome the suggestion of the term homocline. The 

 need of a term for this structure has long been felt in the United States 

 Geological Survey, where confusion has been avoided in editing by using 

 monoclinal for the homocline as distinct from monocline or monoclinal fold. 

 The term homocline will not only be useful in referring to rocks having the 

 same dip, but whose structure is not known, as mentioned by Professor Daly, 

 but also for the beds between an anticline and syncline, to which neither the 

 term limb of the anticline nor limb of the syncline is not appropriate. 



Prof. William H. Hobbs : I wish to add my indorsement of Professor Daly's 

 position and express the belief that the use of homoclinal in the sense of uni- 

 formity of dip will prevent much misunderstanding. A region where such a 

 term might have been used to advantage is that of the Taconic shales in east- 

 ern New York State. Almost by accident I came on much compressed anti- 

 clinal cores in a number of localities which showed the wide zone of westerly 

 dipping shales to be isoclinal, though before regarded as a single limb of a fold. 



7 E. de Margerie and A. Heim : Les dislocations de l'ecovce terrestre. Zurich, 1888, 

 p. 26. 



