* 
232 A. Winchell on Fossils from the Potsdam, etc. 
stems are an inch and a quarter in diameter; the transverse sec 
tion oblong, rounded at the ends, or, in other eases, more nearly 
acircle. ‘The branches are uniformly much smaller than the 
main stem, and leave it at an angle of about 30°. One of the 
most marked peculiarities of the species is the somewhat regular 
transverse constrictions, which occur at intervals of about half 
an inch, in most of the specimens. At these constrictions the 
fucoid has shown a disposition to separate, so that most of the 
fragments present sharply truncate extremities. Surface smooth. 
This fucoid is found abundantly scattered over the surfaces of 
slabs of dark red, fine-grained sandstone, from the north flank 
of the Porcupine mountains, Lake Superior. 
Collected by Dr. Douglass Houghton, in 1840. 
PaLzopuycus INFORMIS, Nn. Sp. 
line. - In some instances it would seem that a hollow, conical 
iece had been compressed so as to present two opposite edges. 
Boiisetivea an irregularly elongate piece presents occasional et- 
largements and tuberculous eminences. ‘here are some indica 
tions that the plant was branched, some of which consist in the 
close approximation of co-adapted edges without complete june 
tio e surfaces are smooth and shining. The fragments 
vary from half an inch to two inches in width. 
Abundant in dark red sandstone from Montreal river, Lake 
sandstone three miles west of Eagle river; and again in wil 
tion of the lowest fossiliferous sandstones 
thought by Messrs. Foster and Whitney, and formerly by #4) 
and still earlier intimated in the unpublished notes of Dr. a 
ton; or finally, as now intimated by Hall, a formation rang 
from a horizon below the fossiliferous sandstones of ¥ 
to the top of the Chazy formation or St. Peter’s sandstone. 
University of Michigan, Dec. 11th, 1863. 
ae 
Paes Sea ene 
