116 



The Lower Devonian Deposits of Maryland 



According to Ulrich's view the beds usually referred to the Manlius 

 formation at Manlius, in central New York, comprise different units 

 which may be discriminated as follows, in descending order : 



r Upper beds — Transition beds. 

 " Manlius " of J Cement beds— Rondout. 



authors. 1 Fossiliferous bed — Decker Ferry ?. 

 L Typical Manlius — Manlius fauna. 



The beds referred to the Manlius formation at Eondout, by other 

 students, are believed by Ulrich to be comparable to the upper beds of the 

 Manlius section, while the Eondout formation is believed to be identical 

 with the cement beds which lie above the typical Manlius in the Manlius 

 section. In other words, the Eondout is held to be younger, and not older, 

 than the typical Manlius. At Manlius this section shows a fossiliferous 

 bed between the cement beds and the typical Manlius which is pro- 

 visionally correlated with the Decker Ferry. The typical Manlius is 

 believed to have pinched out before reaching Eondout where it is repre- 

 sented by a hiatus below the Decker Ferry. Ulrich's view may be repre- 

 sented as follows: 



Section at Manlius 

 Central New York 



Onondaga or Oriskany. 



r Hiatus. 



i Transition beds (Keyser). 

 Lower Devonian -jpj^j^^^^^ 



[Decker Perry ? 

 fTypical Manlius. 

 Icobleskill. 



Silurian 



Section at Rondout 

 Southeastern New York 



Coeymans. 



" Manlius " of authors. 



Rondout. 



Decker Ferry. 



Hiatus. 



Hiatus. 



Ulrich bases his view upon a close correlation of the lithological and 

 faunal zones of the sections at Manlius and Eondout by which he believes 

 he has established the presence of the Eondout above the typical Manlius in 

 the Manlius section. Since the Eondout is underlain by the Decker Ferry 

 with apparent conformity in southeastern New York the latter formation 

 is held to be younger than the typical Manlius and hence distinct from the 

 Cobleskill. 



