acammy of sciences] CH IEF GEOLOGIST, NATIONAL SURVEY 173 



REVISION OF 1902-3 



Not until the winter of 1902-3 was a formal revision of the earlier plan undertaken. A 

 conference was then held, with Gilbert as its chairman, for the purpose of settling certain ques- 

 tions that had arisen as the work of the survey advanced; but the changes resolved upon were 

 mostly of a subordinate nature. 1 One was the merging of the superficial or Pleistocene deposits 

 with other clastic deposits, thus making three instead of four classes of structures to be dealt 

 with. Others were the addition between Cambrian and Silurian of Ordovician, which had 

 been excluded before, and the adoption of Pennsylvanian and Mississippian as subdivisions of 

 the Carboniferous ; also a relaxation of the rule regarding priority in the naming of formations. 

 On the last point Gilbert had previously expressed his opinion in a discussion concerning the 

 name, Newark, proposed by the survey to replace the various names by which the so-called 

 Triassic strata of the eastern United States had been called: 



Much time and ink have been wasted in discussing the claims of alternative stratigraphic names. In many 

 instances controversies arise over matters of fact, but there are also numerous cases in which the facts are well 

 understood, and individuals disagree only as to the bearing of the facts on the questions of nomenclature. 

 Opinions differ so widely as to the principles which should determine the selection of names that facts which 

 some regard as conclusive appear to others not at all pertinent. The road to ultimate peace lies through a 

 war of principles, and the valuable controversy is one in which the fundamental postulates of the contestants 

 are exposed. 



He then proceeds to state the two postulates on which his preference for Newark is grounded : 

 First, the formational unit in question should have a single name over its entire area;, and, 

 second, the name should include a geographical term. Newark is preferred as the geographic 

 term because it has a definite association with the formation under discussion, because it has 

 priority of use, and because it is free from other association with geological terminology. 3 

 Nevertheless, the generally established use of Triassic was in the end allowed to prevail over 

 the effort of the survey to revive an early but obsolete name for use in a way that was in accord 

 with its scheme of systematic terminology. "At a later date, after the action taken by the 

 survey committee in 1903, Gilbert expressed himself characteristically in a "notice" of the 

 new rulings and relegated mere priority to a low rank: 



In all the various discussions as to the choice of names and the determination of principles by which to 

 regulate such a choice no account has been taken of the personal factor. Where priority has been the criterion 

 of selection, it has been used because it affords a rule of simple application, and not because the authors of names 

 are supposed to have "rights" in the matter. For myself I share the view of Darwin, that the accentuation 

 of personal credit for the giving of names is the bane of systematic terminology in biology, and believe that it 

 should be scrupulously avoided in geology. 3 



Thus from first to last Gilbert had a hand, and a very influential hand, in establishing the 

 plan on which the geologic folios of the survey are constructed; he may be regarded as one of 

 the leading architects in preparing the design of what is growing to be a great national monument. 



CORRELATION PAPERS 



Gilbert's duties in connection with the "correlation papers," already alluded to, were more 

 to his taste than administrative tasks, although they interfered seriously with field work. 

 These duties were assumed in 1888, the completion of the Bonneville report and his withdrawal 

 from the charge of the Appalachian division giving him the freedom necessary for them. A 

 conference was held in order to agree upon certain essentials, chief among which was that the 

 units of correlation were to be large time periods, like Cambrian and Cretaceous, and that the 

 correlations were to be based chiefly upon marine invertebrate fossils. Time for study and 

 reflection was here taken freely, both by Gilbert, as editor in charge, and by the authors of the 

 several essays, and as a result an extremely useful series of volumes was eventually issued. 

 The editor's share in their preparation was at first the determination of a plan to be followed 



1 Twenty-fourth Ann. Rept. U. S. Geol. Survey, 1903, 23-27. 



1 The name "Newark" in American stratigraphy. Journ. Geol., ii, 1894, 55-59. 



» Amer. Geol., xxiiii, 1904, 137-142. 



