158 KUMMEL AND WELLER LIMESTONES OF KITTATINNY VALLEY 



Leperditia fahidites, a Black River species of ostracode, is the most 

 abundant form, occurring in great numbers, almost to the exclusion of 

 the other species. The complexion of the fauna, as a whole, is Black 

 River, although none of the species are typically restricted to that 

 *horizon. 



On the same hillside, l3''ing stratigraphically 25 or more feet above the 

 Leperditia horizon, but below it topographicall}'-, there is quite a different 

 faunal zone Avith Parastrophia hemipllcnta (Hall). This Parastrophia 

 zone also occurs in an outcrop just north of Drake's pond, east of New- 

 ton, where the fauna is much better represented, and the following 

 species were collected. : 



1. Columnar ia sp. 8. Platystrophia biforata (Schl.). 



2. Lingulasma sp. 9. Parastrophia hemiplicata {HslW). 



3. Plectambonites sericeiis {Sow.). 10. Pterygometopus calllcepJialus {Hsd\) . 



4. Slrophomena incurmfa (Shep.). 11. Bumaslus Irenlonensis {Emm.). 



5. Orthis tricaiaria {Ck>n.). 12. Isotelus gigas {De Kay). 



6. Dinorthis pectinella {Emm.). 13. Platyuietopus irenlonensis {H&\\). 



7. Balmanella testudijiaria {Da,\.) V2ir. 



In his study of the Trenton faunas in New York, White * has found 

 a Parastrophia zone to i)e quite constantly present at the top of the 

 Black River horizon, and it is possible that the Parastrophia zone in 

 New Jersey is a southern continuation of the same zone as it occurs in 

 New York. Too much dejiendence, however, should not be placed upon 

 the occurrence of Parastrophia hemiplicata, for the same species is known 

 to occur even as hi«;h up as the Lorraine. Orthis tricenaria and Dinor- 

 this pectinella, however, which occur in the fauna, are characteristically 

 low Trenton forms, and Columnaria is usually considered as being t3'pical 

 of the Black River horizon. 



Another faunal zone in the Trenton of New Jersey, which is appar- 

 ently widespread, is characterized by a species of Receptaculites, prob- 

 ably R. occidentalis Salt. Because of the isolated nature of the outcrops, 

 this Receptaculites zone has never been noticed in close association 

 with an}' other zone, so that its exact position has not yet been definitely 

 fixed, although it has been observed at many different localities. It is 

 certainly in the lower portion of the formation and is probably beneath 

 the Parastrophia zon^. Streptelasnia projunda and Columnaria usually 

 occur associated with the Receptaculites. 



The most prolific Trenton fauna in New Jersey, so ftir as observed, 

 occurs on the summit of the hill northwest of Jacksonburg, a small 

 village near Blairstown. This fauna occupies the highest i)osition in 



* Rep. of Director N. Y. State Mus., 1900, p. 28. 



