AN EURYPTERID HORIZON IN THE NIAGARA. 
7 
Whitfieldella nitida Hall ? 
Plate II, figure 2, numerous small specimens. 
Small whitfieldellas are very common in some layers of 
rock; they are generally less than 5 mm. long, vary considerably 
in proportion of length to width, and have sharp erect beaks. 
In all characters excepting the erect beak, this little whitfieldella 
appears to be clearly referable to the species nitida. 
Meristina ? sp. 
Plate II, figure 2, single large specimen, 
A single poorly preserved pedicle valve 12 mm. long by 
9 mm. wide with a well-defined sinus from beak to front is doubt- 
fully referred to this genus. 
Anoplotheca ? sp. 
Plate II, figure 3. 
A single mould of what appears to be a pedicle valve of 
a shell doubtfully referable to this genus, measures 14 mm. in 
breadth and 15 mm. in length. The convexity was never 
great, and was probably most marked about the middle of the 
shell. Crushing has reduced the convexity. The shape is nearly 
circular, excepting for the beak which protrudes slightly. The 
apical angle is about 115 degrees. The plications are straight, 
subangular, and number eighteen. They increase towards the 
margin by bifurcation. 
Conularia niagarensis Hall ? 
Plate II, figure 4. 
One specimen appears to represent this species. It is 
5 cm. long by 3 • 2 cm. wide, and tapers rather abruptly towards 
the apical end. So far as they are preserved, the characters 
of this specimen agree closely with the figures given by Hall 
(Palaeontology of New York, Vol. II, PL 65). The transverse 
