FORMATIONS OF THE SKUNNEMUNK MOUNTAIN REGION 43 



and Weller 1 have designated as the Newfoundland grit, a 

 formation which is transitional into the Cornwall shale and' 

 which has an estimated thickness of about 215 feet. The fauna 2 

 of this grit is essentially that of the Onondaga limestone of New 

 York. The Newfoundland grit 3 as defined by Kummel and 

 Weller is as yet known only in the Green Pond mountain region. 



The relations between the Newfoundland grit as defined by 

 Kummel and Weller and the Oriskany quartzite of the Skunne- 

 munk mountain region is not entirely clear. In the New Jersey 

 section under consideration, none of the Helderbergian rocks 

 are shown, the highest known formation below the Newfound- 

 land grit being the Decker Ferry beds, the upper part of which 

 corresponds to the Cobleskill limestone. For the New York area 

 I have retained the name Oriskany quartzite, w 7 hich term has 

 been used by Darton and by Ries for this quartzite in this region. 

 For the present at least the retention of this term seems the most 

 desirable, for the Helderbergian rocks, if not in actual contact 

 with the Oriskany, are but a short distance below it. Moreover 

 the quartzite at Pea hill is characterized by such Oriskany 

 species as Anoplia nucleata Hall, and Leptocoelia 

 f 1 a b e 1 1 i t e s Conrad. According to Kummel and Weller the 

 Newfoundland grit grades upward into the Monroe shales,, 

 without any line of demarkation. Two species from the 

 Newfoundland beds, Pterinea f 1 a b e 1 1 u m Conrad and 

 Actinopteria decussata Hall, as identified by Kum- 

 mel and Weller are Hamilton forms and they tend to show a 

 close relation of these beds to the Flamilton formation. It is 

 possible that future studies wall indicate that the formation 

 which I have here designated the Oriskany may represent a 

 later return of Oriskany conditions and its fauna. 



In this connection it should be noted that the Esopus, Scho- 

 harie and Marcellus formations which in the typical New York 

 sections lie between the Oriskany and Hamilton formations, have 

 as yet not been observed in the Skunnemunk mountain region. 4 

 The section that approaches most closely to the conditions of the 

 Oriskany as found in the Skunnemunk region, both as regards 

 nature of sediments and relation of the overlying rock, is that 

 of central and western New York, which also includes the type 

 section for the Oriskany sandstone. There the Oriskany, wher- 



^eol. N. J. An. Rep't. 1901. p. 18. 



2 N. J. Geol. Sur. Rep't on Paleontology. 1902 (1903). 3:105. 



3 The term Newfoundland quartzite was first proposed bv Eckel for the quartzite tvpicallv 

 exposed at Newfoundland, N. J. Eckel considered the rock to be paleontologically equiva- 

 lent to the Oriskanv quartzite. See N. Y. State Geol. An. Rep't. 1900. p. ri.48. 



4 See Ulrich & Schuchert, N Y. State Pal. An. Rep't. 1901. p. 654. 



