428 H, N. Eaton — Oriskany Sandstone Faunule. 



to Clarke,^ — and is overlain by the Onondaga limestone. 

 The friable nature of the rock is well known. The upper 

 surface is more quartzitic and darker in color than the 

 lower portions. Dr. Clarke^ noted the abrupt transition 

 here from the underlying limestone to the superjacent 

 Oriskany sandstone, and spoke of its extent as follows: 



''All calcareous beds are here wanting . . . This quality of 

 rock does not occur in any of the eastward exposures of the Oris- 

 kany from Albany County to the New Jersey line except for an 

 occasional thin streak without fossils. From Oriskany Falls 

 westward no calcareous beds appear except toward the top of the 

 deposit as the sedimentation grades into that of the Onondaga 

 limestone above. . . . 



"The character of the Oriskany deposit in New York from 

 Schoharie County westward may be regarded, in a general way as 

 a series of arenaceous lenses (in strike section) connected by thin 

 sheets of quartzitic sandstone. The outcrops at Oriskany Falls 

 and Yawger 's Avoods are such lenticular masses. ' ' 



Fauna. 



Vanuxem^ lists four common Oriskany brachiopods as 

 numerous in the lower part, and figures another brachio- 

 pod, also mentioning the occurrence of a pelecypod. 

 Brigham" mentions Spirifer arenosus (Conrad) emdRens- 

 selceria ovoides (Eaton) as being abundant. Both 

 authors note the occurrence of the fossils as interior 

 casts. Clarke^ lists Chonostrophia complanata (Hall), 

 although this species was not found by the writer. The 

 following is the list of species disclosed by the present 

 study : 



Spirifer arenosus (Conrad), S. murchisoni Castelnau, Rens- 

 selaer ia ovoides (Eaton), R. ovoides (Eaton), var. nov. ?, Hip- 

 parionyx proximus Vanuxem, Meristella lata (Hall), M. laevis 

 (Vanuxem), Eatonia pecidiaris (Conrad), Centronella glans- 

 fagea (Hall) , Leptostrophia (Stropheodonta) magnifica (Hall) ?, 

 Rhipidomella emarginata (Hall), Megalanteris ovalis Hall?, 

 Modiomorpha sp. undet., Actinopteria sp. undet., and Diaphoros- 

 toma ventricosum (Conrad). 



Rensselceria ovoides is a common fossil in the main 

 outcrops and boulders. The possible new variety of this 



*J. M. Clarke, The Oriskany Fauna of Becraft Mountain, Columbia 

 County, N. Y., N. Y. State Museum, Memoir No. 3, p. 78, 1900. 

 = Op eit., p. 78. 



^ L. Vanuxem, Geol. X. Y., part 3, Survey Third Dist., pp. 123-125, 1842. 

 ' Op. cit., p. 109. 

 ^ Op. eit, p. 78. 



