S6 NEW YORK STATE MUSEUM 



In another work, the writer^ has described the Medina of 

 New York under two divisions, namely the lower and the upper,, 

 which may be regarded as corresponding to the Juniata and 

 Tuscarora of Pennsylvania and Mar3dand. The passage from 

 the Lower to the upper is marked by a change in character of 

 sedimentation and in the color of the rock. At the Niagara, 

 river, the lower red shales are followed by about 25 feet of gray 

 quartzose sandstone. This bed of sandstone corresponds ap- 

 proximately to the base of the Oneida or upper Medina from 

 Oneida county eastward, both occurring at a little more than 

 100 feet below the base of the Clinton. This gray sandstone- 

 marks the introduction of marine life into the Medina. At 

 Niagara the gray quartzose sandstone is followed by a series of 

 thin shales and sandstones and is terminated above by the 

 " gray band " w^hich is the upper limit of the Medina. 



It was pointed out in a previous paper^ that the Shawangunk 

 conglomerate of eastern New York, probably represented are 

 age later than the Oneida, with which it had been generally 

 correlated. Though at that time the Oneida conglomerate was. 

 regarded as of the same age as the Oswego sandstone, the pres- 

 ent study shows still more clearly that the Shaw^angunk con- 

 glomerate should not be regarded as basal Medina, but as Salina.^ 



In a recent publication,* Dr. A. W. Grabau has regarded the 

 Oneida as a basal conglomerate, which, in age, ranges from the 

 lower (=Oswego sandstone) Medina to the upper Medina. Irti 

 this connection it should be noted that at the type locality for 

 the Oneida, which is near Verona in Oneida county, the con- 

 glomerate is just below the Clinton and that this relation to the 

 Clinton holds for 40 miles eastward to beyond Vanhornsville in 

 Herkimer county, where is shown the last known exposure of 

 the Oneida to the east, and thus this formation throughout this- 

 extent must be of upper Medina age. 



This fact, together with the Oswego river section, tends to> 

 show that the Oneida wherever known holds a position which is- 

 never far below the base of the Clinton. Hall'^ records the find- 

 ing of a conglomerate or pudding stone at the top of the Medina, 

 at Wolcott in Wayne county. A similar reference is also made 

 to this locality in one of Hall's district reports.® As the top of 



IN. Y. State Mus. Bui. m pre.ss. 



2N. Y. State Pal. An. Rep't. 1903. p. 346. . 



3The reasons for considering the Shawangunk conglomerate as of the age assigned above,. 

 are stated in a paper on "The Siluric and Lower Devonic Formations of the Skunnemunk. 

 Mountain Region" in this bulletin. 



4N. Y. State Mus. Bui. 92. 1906 p. 123. 



SGeol. N. Y 4th Dist. 1843. p. 42. 



6An. Rep't 4th Dist. 1838. p. 323. 



