20 NEW YORK STATE MUSEUM 



bergian limestones farther east and is probably the equivalent of the 

 Coeymans division of that group. There is a little uncertainty 

 concerning the parting between this limestone and the underlying 

 Manlius in this area. 



If the upper limit of the Manlius is the upper waterlime layer 

 of that group, as stated by Hartnagel, 1 then the problem is solved 

 and the Helderbergian limestones extend west almost to the western 

 border of the quadrangle ; but if the upper Stromatopora layer and 

 some of the associated blue limestone is Manlius, rather than Hel- 

 derbergian as implied by Harris, 2 then Harris's further statement 

 that the western limit of the Helderbergian is in the vicinity of 

 Manlius is true and this group is scarcely represented on the Syra- 

 cuse quadrangle. The limestones at this horizon are not markedly 

 different from the blue limestones below the waterlime and the 

 separation must be based on a refined study of the paleontology 

 of the two. In the construction of the map the stratigraphy is based 

 on the Hartnagel section and the Helderbergian extended westward 

 until the upper waterlime and the Oriskany sandstone come together 

 near the Split Rock quarries in the western part of the area. 



Some 2 miles southwest of Manlius, in the southeastern part of 

 the Syracuse quadrangle, there is a thickness of 50 feet of blue lime- 

 stone at the Helderbergian horizon between the Oriskany sandstone 

 and the upper Manlius waterlime. In this section the crystalline 

 crinoidal layer of the Manlius section does not appear at all and the 

 Stromatopora beds have a greater thickness ; in fact, almost the 

 entire thickness of 50 feet shows Stromatopora in abundance. At 

 Jamesville, a few miles farther west, the thickness is 40 feet and at 

 Britton's quarry, 3 miles farther west, it is 12 feet. At the Split 

 Rock quarries on the west side of the Syracuse quadrangle it is not 

 present at all, as the Onondaga limestone rests directly upon the 

 Manlius waterlime. 



ORISKANY SANDSTONE 



The Oriskany sandstone occupies the interval between the Helder- 

 berg-Manlius limestones below and the crystalline Onondaga lime- 

 stone above, and, in connection with the Onondaga limestone, forms 

 the best key rock in working out the stratigraphy of the area. It is 

 a coarse-grained sandstone lying in the midst of a great thickness 

 of limestones and its position in the column need never be mistaken. 



1 Loc. cit. 



2 American Paleontology. Bui. 19. Ithaca, N. Y. 1904. 



