216 n PALEOZOIC PALEONTOLOGY. 
MOLLUSCOIDEA. 
BRACHIOPODA. 
PLECTAMBONITES SERICEUS (Sow.). 
Plate XVI., Figs. 2-3. 
See, also, p. 149, pl. IX. 
In the flagstone quarry at Sussex a thin, arenaceous layer, charged 
with calcareous material, is filled with a few species of fossils, by 
far the most abundant of which is P. sertceus. The specimens are 
all much smaller that the Trenton representatives of the species and 
many of them are proportionately broader. 
PLECTORTHIS PLICATELLA (Hall). 
Plates evel, sie O: 
See, also, p. 152, pl. IX. 
A single incomplete impression of the pedicle valve of this species 
has been recognized from Sussex. Scarcely enough of it is pre- 
served to exhibit its characters properly, but it is apparently less 
nearly circular than the Trenton representatives of the species, being 
proportionally broader, in this respect resembling more closely the 
Cincinnatian representatives of the species. 
DALMANELLA TESTUDINARIA (Dal). 
Plate XVI., Figs. 4-5. 
See, also, p. 155, pl. X. 
The representatives of this species which are present in the Hudson 
River formation at Sussex are usually smaller than those of the Tren- 
ton limestone, but in other respects are not essentially different. 
