CAMBRO-ORDOVICIAN LIMESTONES 



713 



Strophomena ( ? Leptaena) cf . char- 



lottae. 

 Plectambonites asper. 

 P. pisum. 



P, n. sp. (near P. pisum). 



P. n. sp. 



Christiania trentonensis. 

 C. n. sp. 



Triplesia n. sp. 



T. cf. nucleus. 



Protozyga exigua. 

 Orthoceras cf. junceum. 

 O. cf. arcuoliratum. 



Lepidocoleus 2 undet. species (near 



L. jamesi). 

 Isotelus cf. gigas. 

 Illaenus consimilis. 

 Fragments of Trinucleus or Tretas- 



pis. 



In the upper, or Sinuites, zone, which is immediately beneath 

 graptolite-bearing sliales, 3 1 species were collected, and the following 

 determined : 



Diplograptus sp. undet. 

 Lingula riciniformis ? 

 Lingulops sp. nov. ? 

 Conotreta rusti. 

 Rafinesquina cf. ulrichi. 

 Sinuites cancellatus. 

 Cyclora minuta. 

 C. parvula. 



Microceras cf. inornatum. 

 Coleolus cf. 

 Trocholites sp. undet. 

 Caryocaris sp. undet. 



Turrilepas sp. undet. 

 Ctenobolbina sp. undet. 

 Ampyx n. sp. 

 Trinucleus concentricus ? 

 Harpina ottawaensis ? 

 Triarthrus becki. 

 T. fischeri. 



Calymene senaria ? 

 Bumastus sp. ? 

 Bronteopsis ? sp. undet. 

 Proetus latimarginatus. 

 Cyphapis matutina. 



In the Mercersburg quadrangle 4 faunal zones are also distin- 

 guished but they do not correspond with those of the Chambersburg 

 belt. The lower zone comprises 20 species, largely new and unde- 

 scribed, of which the following are tentatively hsted : 



Licrophycus cf. ottawaensis. 

 Lockeia sp. undet. 

 Cliocrinus n. sp. ? 

 Raphanocrinus ? n. sp. 

 Echinosphaerites sp. ? plates only. 

 Helopora spiniformis ? 

 Rhinidictya neglecta. 

 Escharopora ramosa. 



Dalmanella cf. testudinaria. 

 D. subaequata. 



Rafinesquina minnesotensis. 

 Strophomena cf. filitexta. 

 Plectambonites asper. 

 Gonioceras chazyense. 

 Thaleops ovatus. 

 Pterygometopus cf. schmidti. 



Of the 48 species collected in the second zone, the brachiopods 

 and bryozoa that have been identified by Mr. Ulrich are regarded by 

 him as suggesting the upper Chazy of New York: — 



