Potsdam of Wisconsin and Lake Superior. 231 
prominent, with its posterior portion inarticulate and broad] 
rounded, There is no limiting furrow separating it from the 
lateral lobes; and posteriorly it fades insensibly into the ter- 
minal border. The lateral lobes are but faintly articulate, and, 
meeting behind the axis, form a border three-fourths of an inch 
broad, which is strongly curved downward on all sides, and 
presents a circularly curved outline, without any indications of 
caudal appendages. 
The foregoing was written before seeing Prof. Hall’s memoir; 
and I had referred the specimens to Dicellocephalus, with a query. 
I could scarcely doubt of their generic distinctness, but felt re- 
luctant to engage in genus-making without ampler materials. I 
am happy now to recognize Prof. Hall’s new genus as exactly 
meeting my want. This species differs from P. Miniscaénsis Hall, 
in its broader and fuller movable cheek and broader margin, 
and much longer genal points. 
Il. The University has for many years been in possession of 
some fucoidal remains from the red sandstone of the sout 
shore of Lake Superior. As it is so uncertain when any further 
paleontological data will be obtained from that region, I do not 
deem it necessary to defer longer a brief notice of these fossil 
gee 
pe | 
different portions of the fronds of recent marine algz, shows how 
little Pepeniience can be placed upon descriptions founded on 
PaLZopurycus ARTICULATUS, 0. Sp. 
Consisting of large, straight or geniculated, compressed-cylin- 
drical, irregularly articulated, branching stems. The largest 
* 
