DISTRIBUTION AND OCCURRENCE OF EURYPTERIDS 507 



of the Salina formation specifically indeterminable fragments of Hugh- 

 milleria and carapaces of Dolichopterus (cf. D. otisius) or Pterygotus 

 have been found along the Pennsylvania-Maryland border. 104 But of far 

 more interest and importance are the faunas of the Pittsford and Sha- 

 wangunk shales of New York and Pennsylvania. At Pittsford, Monroe 

 County, five species of Eurypterids have been found : Eurypterus pitts- 

 fordensis Sarle, Hughmilleria socialis Sarle, H. socialis var. robusta 

 Sarle, Pterygotus monroensis Sarle, and Stylonurus (Ctenopterus) mul- 

 tispinosus CI. and E. This fauna is represented by numerous individuals, 

 many of them well preserved, and by many fragments, but typical ma- 

 rine fossils are absent from the shales, although other Crustacea, such as 

 Emmelezoe decora and Pseudoniscus roosevelti, occur. The Eurypterids 

 are here preserved in a remarkable state of perfection. The fauna is 

 found in two layers of the black shales, and the Eurypterids are in such 

 abundance that some layers are "literally packed" with the remains. 

 Marine fossils occur, however, in intercalated dolomites. In a loose block 

 belonging to beds regarded as representing the Pittsford horizon, 3 miles 

 south of Clinton, New York, several specimens of Eusarcus vaningeni 

 CI. and E. were found. "The block is also full of Lingirlas and Orbicu- 

 loideas. . . ." Clarke and Euedemann think that -this may be the 

 adult of Eusarcus cicerops of the Shawangunk. From the shale beds in 

 the Shawangunk conglomerate at Otisville, Orange County, New York, a 

 large fauna of Eurypterids has been obtained, but other fossils except 

 Ceratiocarids are absent. The perfect specimens are all of young indi- 

 viduals, some being 2.5 millimeters long, but large individuals are repre- 

 sented only by fragments. The species recorded are : 



1. Eurypterus maria Clarke. 



2. Eusarcus ? cicerops CI. 



3. Dolichopterus otisius Clarke. 



4. D 9 . stylonuroides CI. and E. 



5. Stylonurus {Ctenopterus) cestrotus CI. 



6. S. {Ctenopterus) sp. a, sp. /?, sp. y. 



7. 8. myops CI. 



8. 8. sp. 



9. TTucjli millcria shaivangunk CI. 



10. Pterygotus globiceps CI. and E. 



The Eurypterids occur in thin bands of black shale intercalated be- 

 tween the grit layers, which bear no traces of I he fossils. "While the 

 Eurypterus faunas of . . . Pittsford consist almost entirely of nia- 



104 Pawpaw Hancock Folio, r. S. Geol. Survey Atlas. 



