I 



CONTENTS 283 



Page 



Improbability of iiuiriue scour 362 



Cases indicating local prevention of sedimentation and bottom 



scour by marine currents 363 



Current scour improbable in interior continental seas 365 



Improbability of transcontinental marine currents shown by 

 the geographic limitation of Mohawkian sediments and 



faunas 367 



Evidence of the graptolites on currents in continental basins. 371 

 Progressive overlap structure opposed to theory of current 



scour 373 



The stratigraphic column 375 



Development of the American Paleozoic colunm 375 



Review of the classifications of other authors 375 



Diminishing imperfections of the geologic record 377 



Additions to the Paleozoic column since 1850 379 



Thickness of "Paleozoic" sediments in America 381 



Suggestions concerning nomenclature of stratigraphic units 384 



General discussion 384 



Effect on nomenclature of shifting or modification of boundaries 



of stratigraphic units 384 



Concerning overlapping formations 386 



Local stratigraphic terms 387 



The standard section for America 388 



Broad interpretation recommended for old New York terms 390 



Relation of formation names to time terms 392 



Part II. Criteria and principles of stratigraphic classification 



Diastrophic criteria 394 



Body deformation causing vertical movement of land and shifting of 



continental seas 394 



General discussion and permanence of oceanic basins 394 



Chamberlin's views 395 



Willis's views on permanence of oceanic basins 396 



Periodicity of movements 398 



General discussion 398 



Willis's view on periodicity of diastrophism 400 



Displacement of strandline chiefly relied on in proving perio- 

 dicity of def ormative movements 401 



Results of recent methods of correlation 403 



Differential vertical movements of the lithosphere 405 



Tilting of land areas 405 



Two groups of movements 407 



The movements defined 407 



Varying effects on the strandline 408 



Discrimination of general earth movements 410 



Minor and local tilting 411 



Examples 411 



Oscillation in the southern Appalachian Valley 412 



Oscillations of the Adirondack uplift 415 



Differential movements of the Cincinnati geanticline 416 



