430 A. W. GRABAU PALEOZOIC DELTA DEPOSITS OF NORTH AMERICA 



river waters from the Appalachian land must not be overlooked. The 

 Oswego sandstone is absent here, removed by early Sihiric erosion, which 

 also removed the whole of the Pulaski shales. But a little to the north 

 these formations occur in their full strength, and, as we have seen, the 

 material of which they are made could only have come from the Appala- 

 chians. If the Eurvpterids were river animals at this period of the 

 earth's history, as they certainly were in later Paleozoic time, it is not 

 improbable that their remains will be found in the finer deposits of the 

 Bald Eagle delta. Eurvpterids are said to occur in the Eden of the' Cin- 

 cinnati region,* and these specimens may have a similar origin, being 

 floated into the shallow waters of the interior, as we know that today 

 terrestrial organisms are carried out for hundreds of miles from shore. 

 Of course, the possibility that Eurvpterids were marine organisms during 

 this period of the earth's history must be conceded, but the evidence for 

 this is to my mind not, very strong. This subject will be more fully dis- 

 cussed in a later section of this paper. 



Schuchert 45 correlates the Upper Lorraine (Pulaski) of Xew York 

 with the Mount Hope and Fairmont beds of the Maysvillian, which would 

 make the Oswego the equivalent in time of the Bellevue and perhaps 

 Corryville zones. This seems a sound correlation so far as the typical 

 Lorraine strata of the third Xew York district are concerned. Xorth- 

 ward in Quebec, however, the "Hudson" beds rise higher, being equiva- 

 lent to the whole of the Maysville and a part of the Bichmond as well. 

 Southward in southern Pennsylvania the Martinsburg shale includes the 

 whole interval from near the base of the Trenton to probably Bellevue or 

 Corryville of the Upper Maysville, inclusive, or, in other words, the 

 Upper Martinsburg is the equivalent of the Lorraine and Oswego. West- 

 ward the top of the "Hudson" series likewise rises, being post-Maysville 

 in the Lake Huron region, where typical Richmond fossils occur in the 

 higher beds. In the stratigraphic depression thus left by the rise in the 

 horizon of the top of the "Hudson," northward, westward, and south- 

 ward, lies the Bald Eagle delta, a continental deposit, the base of which 

 rises in proportion and in the same direction as the top of the underlying 

 Hudson, its marine equivalent, rises. The overlap of these delta beds is 

 thus a replacing one away from the source of supply, which was in the 

 older Appalachian land toward the east. The following diagram (figure 

 4) shows the general relation of these strata. 



The Juniata and the Queenston red beds.— -The Juniata formation was 

 named by Darton from its typical development along the Juniata River 



* Private communication from Mr. Ulrich. 



45 Bull. Geol. Soc. Am., vol. 20, Paleogeography of North America, p. 530. 



