E. Billings on the Potsdam Fossils. 337 
i 
Art. XXX.— Additional Note on the Potsdam Fossils ; by 
E. Bitines. 
that they exhibit several of the parts not gate in those upon 
ed. 
Fig. 4, (nat. size). 
b 
ER B 
Fig. 4~ a, A detached cheek showing the small spine of the posterior angle. 
6c, Two specimens of the glabella, showing the spine on the neck segment. 
Simated but rather smooth. These two characters furnish 
Additional grounds for separating the species from 1 anti 
__ Walter), which has the cheeks striated and the posterior angles of 
~ the head only slightly produced into short broadly triangular 
s. 
on 
termination 
2. The neck segment bears a short broad-based spine. The 
St Specimens collected do not exhibit this, but on reéxaminin 
them I think I can see traces of it. Some of the specimens of C., 
ap (Barrande) lately collected in the Primordial Zone of 
_ “atof C. minutus, while others (according to the figures) have 
us it would appear that the presence or absence of a og 
the neck Segment is not always of specific importance and shou 
ome of those from Keeseville turn out to have only a plain — 
“gment we would not perhaps on that ground alone be author- 
Wed to constitute two species. 
Biargtetn stcle, Bur Zein 3 a a You ya 
MM. de Mainten Pema iar Bulletin Geol. Soc, France, 2°. Series, vol. xvii, p. 
And al 
V., 1960, 
ie 
