18 PALEOZOIC PALEONTOLOGY. 
of Mr. E. J. Hough, just back of the mill at Jacksonburg, near Blairs- 
town (Locality 174 A). At this locality the formation is more than 
ordinarily fossiliferous and the fossils are better preserved than usual. 
On the lower slope of the hill the Kittatinny limestone is exposed and 
in the knoll just beyond the slate outcrops, so that the entire thickness 
of the formation is present. A trench was dug, in order to expose a 
continuous section of the formation from its contact with the Kitta- 
tinny limestone, through a thickness of 122 feet. At this point in 
the section, although the top of the limestone had not been reached, 
the trench was discontinued, because the rock surface dipped so deeply 
beneath the surface of the ground that further digging was imprac- 
ticable. It is probable that fifteen or twenty additional feet of lime- 
stone are present in the section before it passes into the overlying 
Hudson River slates. This section was accurately measured, sixty-one 
different beds being recognized, from each of which fossils were care- 
fully collected. This Jacksonburg section through the Trenton hme- 
stone will be given first consideration in the discussion of the Trenton 
faunas, it being the key to the determination of the faunal succession 
in this formation in New Jersey. 
Locality 174 A—The Jacksonburg Section.* 
174 At. Fine-grained, buff-colored, shaley beds, the con- 
stituent material apparently having been de- 
derived from the underlying Kittatinny lme- 
stone. 2 Ab. eee 
1. Strophomena sp. undet. (r). 
2. Rafinesquina alternata (Emm. ) (ri): 
3. Dalmanella subequata (Con.) (aa). 
4. Ctenodonta jerseyensis 0. sp. (rT): 
5. Ctenodonta sp. undet. (r). 
6. Modiolopsis sp. undet. (aie 
7. Undet. pelecypod (r). 
8. Helicotoma sp. undet. (ry 
9. Lophospira sp. undet. (xe 
10. Trilobite fragments undet. Cee 
11. Leperditia fabulites ( Con.) (a). 
* The relative abundance of the species in the various beds is indicated by the 
symbols (a) abundant, (c) common, (/) frequent, (7) rare 
