GEOLOGY OF THE ATTICA AND DEPEW QUADRANGLES 23 



lopods, gastropods and lamellibranchs that make their earliest ap- 

 pearance in this limestone. 



The fauna includes the following species : . 



Manticoceras pattersoni Hall 



Gephyroceras genundewa Clarke 



Tornoceras uniangulare {Conrad) 



Orthoceras atreus Hall 



Styliolina fissurella Hall 



Pleurotomaria genundewa Clarke 



Bellerophon koeneni Clarke 



Phragmostoma natator Hall 



Loxonema noe Clarke 



Pterochaenia fragilis (Hall) 



Honeoyea styliophila Clarke 



Ontaria suborbicularis Hall 



Buchiolia retrostriata (von Buck) 



Paracardium doris Hall 



Melocrinus clarkei Williams 



Plant remains and fish remains also occur. 



WEST RIVER SHALE 



The beds of dark shale that succeed the Genundewa limestone 

 in the Genesee valley to the thickness of about ioo feet were until 

 recently known as the upper Genesee shales. In that locality about 

 65 feet next above the limestone were dark bluish gray shales with 

 thin layers of black shale interbedded at intervals of 3 to 8 feet. 

 The term West River shale is now used to designate these beds on 

 account of their abundant exposure in the West River valley in 

 the western part of Yates county, the remaining 35 feet of the 

 Upper Genesee beds receiving the name Middlesex black shale. 



The thickness of the West River shale is decreased to 30 feet 

 on the east line of these quadrangles and to 15 feet on the west 

 boundary, but the character of the rock is not altered, spherical 

 concretions and occasionally a thin calcareous sandstone flag appear- 

 ing in the shales at nearly all exposures. 



Fossils. The fauna of the West River shale embraces the fol- 

 lowing species, nearly all from the lighter colored shales : 



Bactrites aciculum Hall 



Gephyroceras sp. 



Pleurotomaria rugulata Hall 



Buchiola retrostriata (von Buck) 



Panenka sp. 



Pterochaenia fragilis Hall 



Lunulicardium curtum Hall 



Lingula spatulata Vanuxem 



Orbiculoidea 



Melocrinus clarkei Williams 



