298 proceedings: geoi.ogical society 



The old belief in broad, deep, and long enduring continental seas — • 

 seas that began early in the Cambrian and continued spreading wider 

 and wider until well toward the close of the Ordovician — ^is still held 

 and taught in some of our best universities. But this inexcusable con- 

 servatism is possible only by closing our eyes to the overwhelming ac- 

 cumulation of opposing facts. vSooner or later it must be abandoned by 

 all. In its place the more progressive geologists conceive of smaller, 

 very shallow, and frequently shifting bodies of water, of seas, that filled 

 a given basin in one age and were withdrawn in the next, that returned 

 again and again in familiar patterns, though perchance from different 

 quarters, in succeeding geological ages. In short, seas that migrated 

 in and out of the structural basins — sometimes extending far across the 

 continents and at other times limited to much smaller areas — ^whenever 

 and wherever a formation of the lithosphere demanded corresponding 

 readjustment of land and marine areas. These adjustments were al- 

 ways marked in the stratigraphic record by recognizable signs. 



Each year's field work is disclosing evidence of Paleozoic oscillations 

 previously unknown; and some of them occur in what had seemed 

 altogether unhkely places. The purpose of my paper is to discuss a 

 half dozen or so of the more striking instances that have been discovered 

 since the publication of the "Revision." The first of these is found 

 in central Pennsylvania, the second and third in east Tennessee, the 

 fourth in northeastern Alabama, the fifth in Wisconsin, the sixth in the 

 Mississippi Valley. In the last two the formations lie practically 

 horizontal, in the others they are folded in the usual Appalachian 

 manner. R. W. Stone, Secretary. 



