1 6 THE HABITAT OP THE EURYPTERIDA 



grey or chocolate brown, bituminous dolomites which at some localities 

 include bituminous shales," and to which Williams has given the name 

 Eramosa beds (303, i). 



The bituminous nature of the dolomites and intercalated shales 

 is indicative of near-shore conditions, and since these succeed the 

 more purely marine facies of the typical Lockport, a shoaling or with- 

 drawal of the sea, with a greater dominance of terrestrial sedimenta- 

 tion, is implied. The fauna is confined within some six inches of the 

 bituminous shales and though fragments of a dozen or more species, 

 including one eurypterid, have been found in abundance, not even 

 generic identifications could be made with certainty. Williams gives 

 the following list (303, 3): 



Eusarcus logani Williams 



Monomorella cf. orbicularis Billings 



Orthis ? near tenuidens Hall 



Spirifer radiatus Sowerby ? 



Anoplotheca ? sp. 



Lichenalia concentrica Hall 



Orbiculoidea subplana (Hall) 



Camarotoechia whitei (Hall)? 



Whitfieldella nitida Hall? 



Meristina ? sp. 



Conularia niagarensis Hall? 



Conularia sp. 

 The Lower Siluric occurrences, thus, are in formations contain- 

 ing undoubted and abundant marine faunas, but the eurypterids 

 are represented either by fragments, or, in the case of the Guelph 

 specimen, by a single though nearly perfect individual. 



A recent discovery of considerable interest is the finding by Pro- 

 fessor Van Ingen of Princeton University, of eurypterid remains in 

 what appears to be the Tuscarora and associated beds of Swatara 

 Gap, Lebanon County, Pennsylvania (39, 418, 419). In beds carry- 

 ing Arthrophycus harlani ? he found: 



1. Eurypterus maria, Large and small carapaces. 



2. Dolichopterus cf. otisius. Medium sized carapace. 



3. Stylonurus my ops. Large and small carapaces . 



4. Hughmilleria shawangtmk. Large carapace. 



5. Pterygotus cf. globiceps. Small carapace. 



6. Swimming leg of a Pterygotus or Hughmilleria. 

 Another bed labeled 182 B 23 has afforded a carapace not distin- 



