DISTRIBUTION AND OCCURRENCE OF EURYPTERIDS 505 



(Claypole) in the Ivokomo beds, Professor Claypole says: "The condi- 

 tion of the fossils precludes very minute details. They are for the most 

 part merely black impressions on the surface of the gray limestone. In 

 some cases a thin scale can be seen, but it exhibits no structure. . . . 

 The general outline is, however, remarkably sharp and distinct." 102 



A recent discovery of considerable interest in the Lower Siluric rocks 

 of Pennsylvania is that by Professor Van Ingen, of Princeton University, 

 of Eurypterid remains in what appears to be the Tuscarora and associ- 

 ated beds of Swatara Gap, Lebanon County, Pennsylvania. 103 In the 

 beds carrying Arthrophycus harlani (?) he found: 



1. Eurypterus maria. Large and small carapaces. 



2. Dolicliopterus cf. otisius. Medium-sized carapace. 



3. Stylonurus myops. Large and small carapaces. 



4. Hughmilleria sJiawangunh. 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 distinguish- 

 able from Eurypterus maria. In a bed said to occur between a horizon 

 containing what is apparently a Clinton fauna (B 8 x) and one contain- 

 ing a Eochester (or Lockport) fauna (B 19 x), and numbered B 16 h, he 

 found the following remains : 



1. Small carapaces, belonging to species closely related to or identical 

 with Eurypterus maria, Hughmilleria shawangunk, and Pterygotus 

 globiceps. 



2. A patch of integument, with finely preserved sculpture, identical 

 with that ascribed to Stylonurus sp. a. 



3. Stylonurus myops. Fragmentary, medium-sized carapace. 



4. Coxa, probably belonging to Hughmilleria. 



5. Small telson of an Erretopterus. 



The earliest European Eurypterid remains are found in the Llandovery 

 (Lower Siluric) of Eastnor Park, England. Fragments of Pterygotus 

 problematicus Salter have been found in the May Hill sandstone, or 

 Upper Llandovery, a basal sandstone resting by overlap on various earlier 

 formations, even on the Shineton (Dictyonema) shales at Wenlock Edge. 

 There is everywhere a marked break and unconformity between the 

 underlying beds and the May Hill sandstone, indicating thai the latter 

 was the first formation of an advancing sea and may have been a terres- 

 trial deposit reworked. Therefore the fragments of Pterygotus found 



102 American Geologist, vol. vi. p. 2(50. 



103 Discussed by Clarke and Ruedemanii, Memoir 14, pp. lis HO, 



