54 Bulletin of Wisconsin Natural History Society. Vol. 1, Xo. 1. 
iron oxide, while the organic remains are much more numerous. 
Several new forms appear among them, the Crinoids, which, while 
not numerous, being mostly confined to this layer, and Phacops 
rami, which has been sparingly observed through the group, be- 
coming more numerous. 
Number seventeen is estimated at about I2 inches thick. It is 
more compact than number i6, with the same character of break- 
ing into minor layers, some of which are more oxided than others 
and rather earthy. Others are very hard, due to not only the calcite 
they carrv but also to the immense number of calcareous fossils 
contained therein. In some parts it is almost a compact mass of the 
Brachiopods of the group, while the disks of crinoid stems are al- 
most innumerable, though with the exception of a small form of 
7 aa'orr/;/zf^ almost no other species of crinoid has been found. Many 
corals are observed, Phacops becomes more common, while a 
species of Proetus is confined to it. Another portion is almost a 
compact mass of Choiictes, while Tajitaciilites is not rare. Over- 
laying the formation at various points are found beds of clay de- 
rived from now unknown layers that have been resolved or de- 
composed. These contain well-preserved specimens of all the 
species found in the upper layers, especially of those found in 
number seventeen, many of which are very abundant, the most 
numerous being those ot Atrypa, Cyrtina and CJionetes. 
While the formation may be said to have three main subdi- 
visions, the lower being the layers numbers one to seven inclusive,, 
which possess much the same general character ; the fossils are in 
almost all cases in the form of impressions. The central subdi- 
vision, or the layers numbers eight to eleven, is of a distinctly 
difterent feature in all of its characters, being very much harder 
in structure, and the fossils in almost all cases being casts of the 
interior ; while the upper subdivision consisting of the layers num- 
bers twelve to seventeen and the clays overlaying them, possess 
many of the characters of both of the lower subdivisions. A\'e 
find the fossils here in much the best state of preservation, yet 
there are verv- few species found in one subdivision but what can 
be found in the others. The greatest number of specimens, how- 
ever, are found in the upper portion. 
While the number of species found is very large for so lim- 
ited an area, the total being over two hundred, the casual visitor 
to the locality will undoubtedly meet with much disappointment, 
as it is only by persistent collecting that anything like a fair 
representation of the fauna of the locality can be secured. 
The observations presented herein have been gathered during 
a period of about twenty years of steady collecting at the locality, 
and while probably not infallible they are as the formation and its 
