STRATIGRAPHIC RELATIONS OF THE ONEIDA CONGLOMERATE 33 



of Eaton," " gray band of Rochester " ; being a sandstone to the 

 west, and a conglomerate and sandstone to the east. 



In the final report of the district geologists, Vanuxem alone 

 defined the Ontaric system as above stated. Hall and Emmons 

 included the Oneida conglomerate as the highest member of 

 the Champlainic system and the Medina sandstone as the lowest 

 member of the Ontaric or Upper Siluric. Mather, however, was 

 more in harmony with Vanuxem and the Shawangunk con- 

 glomerate [p. 2] alone was included in the Ontaric system. 

 However, the other members present above the conglomerate 

 were referred to by Mather as the [p. 353] " pyritous strata and 

 red shales and grit." In his report [p. 2] this conglomerate is 

 designated the " Oneida or Shawangunk conglomerate." 



In a " Review of the New York Geological Reports," contained 

 in the American Journal of Science [Ser. 1. 1844. 47:354], the 

 writer of the article follows Emmons and Hall and includes the 

 Oswego sandstone and Oneida conglomerate in the Champlainic 

 division and the Medina sandstone is made the base of the 

 Ontaric. 



In publications following the final reports of the district geolo- 

 gists, the Oneida gradually came to be regarded as belonging 

 to the Ontaric, to which place it had been assigned by Vanuxem. 

 Among the reasons advanced for regarding the Oneida as 

 Ontaric was the presence of Fucoids, either identical or closely 

 allied with Arthrophycus alleghaniensis, a fossil 

 very common in the upper portion of the Medina sandstone. 1 



On the other hand, the stratigraphic position of the Oneida 

 given by Vanuxem as above the Medina has, in the past, not 

 been retained. In nearly all publications from Vanuxem's report 

 to the present time, the Oneida when considered as a distinct 

 formation has a position below the Medina. In this connection 

 it is interesting to note that in a letter to one of the editors of 

 the American Journal of Science [Ser. 2. 1864. 38:121], Col. E. 

 Jewett, " states that he has found Arthrophycus h a r - 

 1 a n i , a characteristic Medina fossil, in the Oneida conglomer- 

 ate, near Utica, Oneida co., N. Y., and also as he observes, for 

 stratigraphical reasons, that the Oneida conglomerate is in fact 

 only a northern portion of the Medina sandstone. The occurrence 

 of this or a related fucoid is stated by Dana in his Manual of 

 Geology [1863, p. 230], a specimen having been obtained from 

 the rock near Utica by the author more than 30 years since, 

 which was in all probability of the same species, although, as 



iDana, J. D. Manual of Geology. 1863. p. 231. 



