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NEW CRINOIDS FROM THE CHICAGO AREA. 
BY ARTHUR WARE SLOCOM 
In the fall of 1905 the attention of the writer was called to the fact 
that fossils were being found at a quarry operated by the Illinois Steel 
Company for limestone for flux, at Romeo, Illinois. Upon visiting the 
quarry it was found that not only was the limestone itself fossilferous, 
but that silicified fossils were abundant near the bottom of large 
clay pockets which were exposed at various places in the quarry. 
These clay pockets occupy large, irregular shaped cavities in the lime- 
stone. The larger ones are 15 or more feet deep and their width is 
often greater than their depth. In some instances several are connected, 
their connections following the jointing of the limestone. These 
cavities, or “‘pot-holes’’ as they are sometimes called, often associated 
with furrows, are to be seen in many places along the Chicago Drainage 
Canal where the surface of the rock is exposed. The cavities vary in 
size from a fraction of an inch in depth to those mentioned above. 
These cavities or pot-holes must have been in part subjected to the 
action of running water since their sides are smooth. They are fre- 
quently broader at the base than above and may even be cone-shaped, 
with the apex of the cone above. Their filling is for the most part 
a blue homogeneous clay. This contains small silicified fossils of Niag- 
aran age, small, modern, fresh-water shells and fragments of pyritized 
and charred wood. No large boulders or pebbles occur in the clay, 
although these frequently form a capping of the pockets. The question 
of the origin of the filling of the pockets is a matter of no little interest. 
The clay could not be of preglacial origin because of its content of 
wood and modern shells. If of postglacial origin, the presence of 
the Niagaran fossils is difficult to account for. A wall of the quarry 
showing typical pockets is represented in Plate LXXXII. A single 
one in more detail is represented in Plate LX XXIII. 
During the fall of 1905 and the spring and summer of the following 
year, over 400 fossils representing 38 species were collected by the 
writer from these clay pockets. These fossils were divided as follows: 
BREAN Stig Ais? fs. } ottee Eta weedy. tao i PR 293 Specimens, 15 species; 
PEGE hi okt oy ate aR ee Pe px eO Specimens... 3 Species; 
Biss CO ZOANGS orew ecte he BSR see ias ay tA I2 specimens, 4 species; 
