608 e. o. ulrich revision of the paleozoic systems 



Sequence, Grouping, and Nomenclature of stratigraphic Units 

 in southeastern north america. 



general discussion 



We have now reached the point where the foregoing criteria and 

 principles are to be applied as consistently as may be in the prom- 

 ised reclassification of the stratigraphic sequence in North America. 

 Granting, first, that the old classification is, to a certain extent, wrong 

 in principle; second, that the science of stratigraphy has outgrown the 

 old scheme so far that it no longer fills the requirements of the modern 

 taxonomist, and, third, if we admit the competence of the criteria 

 discussed in preceding parts of this work, reclassification of geologic 

 time seems an imperative necessity. At present, then, the only ques- 

 tion is, are the principles which have been deduced from the facts in 

 hand valid enough to insure a reasonable term of stability to the re- 

 vised conception? In other words, are our facts sufficiently numerous 

 and is my interpretation of the evidence sufficiently true to insure a firm 

 basis for the principles of correlation and taxonomy, and thus for the 

 scheme which has been built upon them? That I think so is apparent, 

 for otherwise 1 should not have dared to offer it. Yet, realizing the 

 gravity of the occasion, the sanctity of the institution that I am seeking 

 to tear down and replace with what I deem a more natural and more 

 systematically constructed scheme, it is with great diffidence that I 

 present my conclusions. If a defense were necessary, I might point out 

 how I have worked long and hard ; first, in gathering the data, of which 

 only a small part could be adequately presented at this time, and, second, 

 to shape my results so that they might be truly constructive and not 

 merely destructive. To what extent I have succeeded time alone may 

 tell. Doubtless, certain parts of my correlation tables will be found de- 

 fective, if not altogether erroneous, in matters of detail. We may, too, 

 find it necessary to revise them in relatively fundamental features. But, 

 even if it should prove that the work be faulty in important particulars, 

 the effort must still be set down as worth while, because I know it is 

 not all wrong; some of the new principles, at least, are sound. And 

 that is as much as any of us has a right to expect. 



Whatever of weakness may hereafter be shown in the proposed classi- 

 fication will probably arise from the fact that it is based chiefly on 

 personal observations in the southeastern quarter of the North American 

 continent. This area, though large, is yet but a small part of the entire 

 globe. On the other hand, it comprises the most complete and best 

 exposed sequence of Paleozoic deposits known. Certain parts of the 



