20 NEW YORK STATE MUSEUM 



Phacops rana Green 



Tentaculites gracilistriatus Holl 



Palaeoneilo tenuistriata Hall 



Pholidops hamiltoniae Hall 



Spirifer tullius Hall 



Sp. consobrinus d'Orbigny 



Chontes deflectus Hall 



C. mucronatus Hall 



Leptostrophia perplana (Conrad) 



Ambocoelia umbonata (Conrad) 



Atrypa reticularis Linne ' 



A. spinosa Hall 



Streptelasma rectum Hall 



Cystiphyllum conifollis Hall 



Exposures. The Moscow beds are advantageously exposed along 

 Bowen brook 2 miles northwest of Alexander ; along Murder 

 creek between Griswold and Darien; in the bed of EUicott creek 

 from the fall one and three-fourths miles west of Darien Center to a 

 low cascade 35 rods below the Erie Railroad bridge; in the Erie 

 Railroad cut 2 miles east of Alden ; in a ravine 2 miles southeast of 

 West Alden ; 6 feet of upper beds on Little Buffalo creek half a mile 

 below Marilla ; and especially fine and conveniently accesssible ex- 

 posures are in the Buft'alo Creek gorge above the falls at the Bullis 

 bridge 2 miles west of Marilla; in the Cazenovia Creek gorge at 

 Spring Brook and in a small ravine 2 miles north of Websters 

 Corners. 



TULLY HORIZON — PYRITE LENSES 



The Tully limestone that succeeds the Moscow shale in central 

 New York and is 30 feet thick in Onondaga county, thins out 

 toward the west to Ontario county and is not known west of Can- 

 andaigua lake. In its place there appear at frequent intervals 

 along the line of outcrop of this horizon, thin lenticular masses 

 or lentils composed almost entirely of iron pyrites. These lentils 

 in a few instances attain a thickness of 4 to 5 inches, but are usually 

 less than 2, and they vary greatly in breadth, ranging from a few 

 feet to the entire length of exposure many rods long. 



Fossils are quite common in the pyrite and are mostly of species 

 common in the Moscow or Genesee shales, but greatly reduced in 

 size. A list prepared by Dr F. B. Loomis, published in New 

 York State Museum Bulletin 69, contains the names of 48 species 

 collected from the pyrite in this horizon in Ontario and Livingston 

 counties. Most of these are pigmy forms of well-known species 

 reduced to about one-fifteenth of their normal size. The more 

 abundant forms are : 



