[From the American Jour, of Science and Arts, Vol. XXXYII, March, 1864.] 
Notice of a small collection of Fossils from the Potsdam Sandstone of 
Wisconsin and the Lake Superior Sandstone of Michigan. 
BY PROF. ALEXANDER WINCHELL. 
* * 
The University of Michigan is in possession of a small collec¬ 
tion* of fossils from the Potsdam Sandstone of Sauk county, 
Wisconsin, contributed by one of the alumni , Joseph W. Wood. 
The interest which attaches to every vestige of organic life be¬ 
longing to this age induces me to offer a few words in reference 
to the new data in my possession. 1 
Mr. Wood, in transmitting the specimens, writes: * * * 
“ They are found overlying, and in connection with, the “ quartz¬ 
ite” of the Devil Lake 2 and Baraboo Bluffs. * * * The quartz¬ 
ite is an* indurated sandstone containing ripple marks in abund¬ 
ance—also conglomerates, and, in places, thin layers of talcose 
slate. It has been upheaved along an east and west axis, * * * 
the main ridge pushing the Wisconsin river to the east, where 
it almost forms a junction with the Fox, and at which point the 
two are joined by a canal. There are many minor ridges, run¬ 
ning both parallel and crosswise.” About three miles south of 
the village of Baraboo, the main ridge has been broken open, 
forming an anticlinal valley, in which rests Devil Lake—the 
semi-stratified quartzite dipping rapidly toward the north-north¬ 
east on the east side, and rapidly toward the northwest on the 
west side, and forming bluffs 450 and 500 feet high on the two 
sides respectively. The longer axis of the lake is transverse to 
the main axis of the ridge. South of the bluff, on the east side, 
and beginning opposite the southern portion of the lake, is a 
low, level valley, which extends eastward to the Wisconsin 
river. South of the valley, and bounding the lake at its south¬ 
ern extremity, is a low bluff presenting nearly horizontal strati¬ 
fication ; but probably dipping gently southward, since, in the 
region three or four miles farther south, it supports the first out¬ 
liers of the Calciferous. sand rock. 
The high bluffs surrounding the lake are described by Mr. 
Wood (and also by Prof. Hall in the Wisconsin Report) as con- 
1 The present paper was written and accepted for publication in this Journal be¬ 
fore I had become aware of the existence of the very important paper recently 
issued by Prof. Hall on the Potsdam sandstone of the Northwest. Of the patience 
and research whose results are set forth in this exhaustive monograph, I here express 
my great admiration. It will nevertheless be observed that Prof. Hall’s monograph 
does not embrace a notice of any fossils found as far south as those which form the 
subject of this paper; and I feel that some interest must still attach to the descrip¬ 
tions which are here presented. It will appear evident that a few features have 
been added to the present paper since the appearance of Prof. Hall’s monograph. 
Other recent information from Mr. Wood has also been incorporated. 
9 Sometimes improperly styled “ Spirit Lake.” 
