REPORT OF THE STATE TALEONTOLOGIST 1901 661 



The second important movement occurred at the close of the 

 Beekmantown, when the Mississippian sea was restricted to 

 much narrower limits, and possibly almost drained for a short 

 time. With this emergence, which was unusually abrupt and far- 

 reaching in its results, a new fold was developed along the 

 w^estern side of the Appalachian valley extending from Alabama 

 to Newfoundland. This we call the Appalachian valley fold or 

 barrier, its northern end being distinguished as the Quebec 

 barrier and the southern end as the Kome barrier. There is 

 some reason to believe that the Cincinnati axis or parma had its 

 inception in this second movement, though it did not reach the 

 surface of the sea till long after, i. e., about the close of the' 

 Black river. 



The third pronounced movement occurred at the close of the 

 Ordovicic, when the elevation begun at the close of the Frank- 

 fort culminated in the emergence of apparently the whole con- 

 tinent. It gave birth to the Taconic mountains and to a third 

 long Appalachian fold, called the Helderbergian fold or barrier, 

 that excluded the waters of the Mississippian sea from the 

 Cumberland basin, which thereafter was occupied by Atlantic 

 waters till the close of the Esopus. 



The next invasion of the Mississippian sea began possibly very 

 soon after the Kichmond emergence, bringing in the Medina, 

 Clinton, Niagara and Guelph faunas, the sea apparently spread- 

 ing a little farther with each succeeding formation. Then a 

 period of emergence set in, continuing in the Mississippian prov- 

 ince till Onondaga time, if we disregard the geographically 

 limited Helderbergian invasion of Tennessee and southern 

 Illinois. 



The period of submergence following this gradual emergence 

 of the Mississippian province also was one of slow action, begin- 

 ning with very late Oriskany or Esopus time and continuing 

 apparently into the Lower Carbonic. However, considerable 

 land areas were developed toward the close of the Devonic, so 

 that the rocks of this system also bear evidence of, first a peri- 

 odically progressing submergence and then an emergence like 

 those more clearly shown for the preceding systems. Similar 

 movements are indicated again for the Lower Carbonic and the 

 .Upper Carbonic. 



