446 



A. W. GRABAU PALEOZOIC DELTA DEPOSITS OF NORTH AMERICA 



erable hiatus existed between the 

 two. At the Susquehanna Gap at 

 least 10 feet of this Medina series is 

 shown underlying the Tuscarora. 

 These beds will be more fully dis- 

 cussed in a later section. 



Tli e Bays sandstone — General re- 

 sults of studies made. — This sand- 

 stone, formerly also called Medina 

 and generally correlated with that 

 formation, appears at present to be 

 restricted to the eastern counties of 

 Tennessee and the adjoining area of 

 southern A^irginia and West Vir- 

 ginia and parts of eastern Kentucky. 

 Fairly satisfactory descriptions of 

 this formation are given in the folios 

 of the Geological Atlas of the United 

 States covering this section. 63 In 

 the summer of 1906 I spent several 

 weeks in the field studying this for- 

 mation in Virginia, West Virginia, 

 and Tennessee, and at that time I 

 arrived at essentially the conclu- 

 sions here given. Some of these 

 have elsewhere been stated in print, 

 but the entire problem has not been 

 presented heretofore. It should be 

 stated that my published conclusions 

 have been severely attacked, but such 

 attack has not found its way into 

 print. Subsequently many of these 

 conclusions have been generally 

 adopted, especially those regarding 

 the general Upper Ordovicic age of 

 the formation. At the end of the 

 present review I find myself stand- 

 ing essentially where I stood seven 



63 See especially numbers li 

 \1, 33, 44, and 118. 



16, 25, 2G, 



