STRATIGRAPHIC RELATIONS OF THE ONEIDA 

 CONGLOMERATE 



BY 



C. A. HARTNAGEL 



The Oneida conglomerate is a formation which has long been 

 known in New York geology. Occupying as it does, in sections 

 where it is best known, a position directly above the Lorraine 

 shale, and being composed of coarse pebbles, it has always been 

 easy to recognize. 



This conglomerate was early described by Emmons^ under 

 the name of " millstone grit," and the stratigraphic position 

 assigned to it by him was above the " graywacke," or " metal- 

 liferous graywacke," and below the " saliferous rock." The 

 former corresponds to the Lorraine shale and the latter to what 

 is currently known as the Medina, though the " saliferous rock " 

 was in many cases, as an examination of his text shows, con- 

 fused with the Vernon red shales of the Salina, and in Herkimer 

 county with the Clinton, since in the latter localit}^ the gray 

 band of the Medina is correlated with the upper Clinton sand- 

 stone.^ 



Outcrops of the conglomerate were noted by Emmons from 

 Steele's creek near Ilion and westward at several localities to 

 the south of Utica, and from here west as far as 3 miles 

 south of Rome. Another locality [p. 35] mentioned by Emmons 

 is at the lower Genesee falls at Rochester, This statement, 

 however, is clearly an error, as this locality is again mentioned 

 for the " gray band " which Emmons placed above the Medina 

 or " saliferous rock." That Emmons did not intend to include 

 the " millstone grit " in the rock series at the above locality is 

 shown by his statement on page 96 where he says, " There 

 (Rochester) the red saliferous rock being the lowest in view, 

 this (the millstone grit) is undoubtedly concealed below it." 

 The result of the observations of Emmons as shown by his text 

 and the plate accompanying was that the Oneida conglomerate 

 occupied a position below the red Medina and that the con- 

 glomerate extended as a concealed formation westward beyond 

 the limits of the State. 



^Geological and Agricultural vSurvey of the District adjoining Erie Canal. 1824. p. 35, 95-102 

 ^See Vanuxem. Assembly Doc. 1838. No. 200, p. 268. 



