44 PALEOZOIC PALEONTOLOGY. 
18. Platymetopus trentonensis (Hall). 
19. Enerimurus trentonensis Wale. 
20. Calymene senaria Con. ; 
21. Ceraurus pleurexanthemus Green. 
22. Pterygometopus callicephalus (Hall). 
This fauna suggests a lower Trenton horizon, but is not from the 
lowest, or Orthis tricenaria, zone, as none of the species characteristic 
of that zone have been found, but it is rather from the next succeed- 
ing, Parastrophia hemiplicata, zone. The rarity of the pelecypod and 
gastropod elements in the fauna exclude it from the upper Trenton. 
Locality 158 A.—Along the same line of outcrop as the last locality, © 
and at a point about one and one-fourth miles in a southwesterly direc- 
tion,* another collection was made from the Trenton limestone, and 
the following species have been identified : 
1. Streptelasma corniculum Hall. 
2. Prasopora simulatri« Uly. 
Monotrypa sp. wndet. 
4. Callopora sp. undet. 
5. Rafinesquina alternata (Kmm.). 
6. Plectambonites sericeus (Sow.). 
Strophomena incurvata (Shep.). 
8. Plectorthis plicatella (Hall). 
9. Dalmanella testudinaria (Dal.). 
10. Parastrophia hemiplicata (Hall). 
11. Zygospira recurvirostris (Hall). 
12. Bumastus trentonensis (Eimm.). 
13. Platymetopus trentonensis (Hall). 
14. Hnerinurus trentonensis Wale. 
15. Pterygometopus callicephalus (Hall). 
The horizon here represented is essentially that of the upper fauna 
in the last locality, viz., the Parastrophia hemiplicata zone of the 
lower Trenton. 
Locality 158 B.—This locality is nearly one-half mile southwest of 
the last, along the same line of outcrop, and nearly opposite an 
abandoned slate quarry. The following species were collected : 
1. Callopora sp. undet. 
2. Rafinesquina alternata (Emm.). 
3. Plectambonites sericeus (Sow.). 
*See Map No. 17, loc. cit. 
