14 NEW YORK STATE MUSEUM 



quadrangles. There is a quite extensive field exposure at Stafford, 

 from which village the name is taken, and the limestone appears 

 in the cliff below Main street bridge in LeRoy, and also below the 

 mill at Ashantee, near Avon. 



CARDIFF SHALE 



The upper beds usually included in the old term Marcellus and 

 designated by Vanuxem the "Upper shales of Marcellus," are 

 abundantly exposed near Cardiff, Onondaga county, and have been 

 named from that locality (New York State Museum Bulletin 63, 

 page 16). 



The Cardiff shales decrease in thickness from the type locality 

 westward to about 50 feet here, and also become much darker and 

 more bituminous. On these quadrangles they vary but little in 

 character from the shales below the Stafford limestone, though 

 on the whole a little more calcareous and, after exposure, lighter 

 colored. At the top there is a stratum of impure limestone 12 to 

 15 inches thick, quite hard but somewhat shaly in old exposures. 

 The shales at the base and the limestone near the top of the for- 

 mation are moderately fossiliferous, but the intervening beds are 

 usually not rich in fossils. 



The following forms have been reported from the calcareous 

 lower shales overlying the Stafford limestone at Lancaster : 



Ceratopora dichotoma Grabau 

 Chonetes lepidus Hall 

 Liorhynchus limitare (Vanuxem} 

 Atrypa reticularis Linne 

 Ambocoelia umbonata (Conrad) 

 Meristella barrisi Hall 

 Pterochaenia fragilis (Hall) 

 Styliolina fissurella Hall 

 Orthoceras aegea Hall 

 Phacops rana Green 



Tornoceras uniangulare and Orbiculoidda 

 m i n u t a are common in these beds in Livingston and Ontario 

 counties but are very rare here. 



The only exposures of the Cardiff beds on these quadrangles are 

 on Cayuga and Plumb Bottom creeks in Lancaster, where 2 or 3 

 feet of the lower shale succeeds the Stafford limestone, and at the 

 junction of Cayuga and Little Buffalo creeks one-half mile east 

 of Lancaster, where the hard layer mentioned (which here con- 

 tains fine specimens of Phacops rana) is exposed under the 

 highway bridge. The shale next above this hard layer for 10 to 12 

 feet belongs to this formation. 



