362 A. W. GRABAU — 8ILURO-DEVONIC CONTACT IN NEW YORK 



all the time that the Lower Devonian rocks were accumulating in eastern 

 New York. 1 fully agree with this view, and from evidence given above 

 it appears that this condition extended westward. 



No fossils have been found in the bed supposed to represent the Oris- 



kany, and this identification, based only on the position of the rock, is 

 not to be considered as strictly correct. These accumulations of shale, 

 sandstone, and conglomerate may have occurred at any time during the 

 long interval marked by the accumulation of the Helderbergian, Oris- 

 kanian, and Lower Ulsterian rocks in eastern New York and the devel- 

 opment of their faunas. These thin intermediate beds bear no neces- 

 sary time relation to the Oriskany sandstone of central and eastern New 

 York, and they are correlated with this horizon merely on stratigraphic 

 evidence. 



These intermediate beds are not restricted in occurrence to the region 

 about North Buffalo. Hall * states that in the eastern portion of the 

 count}- — 



"In the town of Newstead a mass of partially decomposed clay and sand lies 

 between the Waterlime and Onondaga limestone ; it is about six inches or a foot 

 thick, highly stained with iron, and exhibiting a partially conglomerated appear- 

 ance. In this are several peculiar coralline fossils. It occupies the place of the 

 Oriskany sandstone, and is its only representative." 



The fossils have never been described and their affinities are unknown. 



ONONDAGA LIMESTONE 



This is the only representative of the lower Middle Devonian (Ul- 

 sterian of Clarke and Schuchert) in western New York, both the Esopus 

 (Cauda-galli) and Schoharie grits being absent. The lower portion of 

 this limestone is crystalline and free from chert, commonly highly fos- 

 siliferous and varying greatl}' in thickness. In the cement quarry in 

 North Buffalo it is usuall}' 2 to 3 feet thick, except above the thin stratum 

 of conglomerate, the thickness there being nearly 10 feet, decreasing rap- 

 idly on all sides. On Skajaquada creek, Bishop gives its thickness as 

 3 to 5 inches at the Main Street bridge and 7 feet in Forest Lawn cem- 

 etery. In the Park quarry it is 51 feet thick, while at Fogelsonger's 

 quarry, in Williamsville, it has a thickness of 35 feet. "At Young's 

 quarry, 2 miles farther east, it is 30 to 35 feet thick, but thins out rap- 

 idly beyond to a thickness of 3 to 5 feet."t At the two quarries last 

 mentioned the rock is chiefly a mass of coral, the remains of an ancient 

 coral reef. 



* Hall, L843, l>. 472. 

 f Bishop, 1895, p. 313. 



