274 Fretp CotumB1aN Museum — Geo tocy, VoL. II. 
Crinoids #330 ee ee eee 21 specimens, 7 species; 
BrachiopOds 0S iee 2s cries earn 96 specimens, 9 species; 
Trilobite; \ <7 Rice sere we eee ane eee 1 fragment. 
Of this material the corals, sponges and crinoids showed a great sim1- 
larity to those found at St. Paul, Indiana, and Perry county, Tennessee, 
and a number of species described from those localities were recognized. 
It was found that the manner of preservation of the clay pocket fossils 
differed from that usual to those of the limestones of the Chicago 
Area in that the latter are natural casts and molds,while the clay-pocket 
fossils are silicified. Search in the surrounding limestone at Romeo 
failed to show similarly preserved fossils in place there and only a few of 
the clay-pocket species were discovered. The spoil heaps of the Chicago 
Drainage Canal were then studied and near Lemont, Illinois, the species 
found in the clay began to appear, until all the brachiopods and part 
of the corals were found. Many of these were in a similar state of 
preservation to those of the clay pockets. Of the seven species of 
crinoids occurring in the clay three were found in the Lemont limestone 
and three more were represented by species of the same genera. Over 
400 fossils, representing 76 species, were collected at this locality, 
divided as follows: 
SpOrigess ) iyi in ee sere a eee 3 specimens, I species; 
Corals Pe ee ee 40 specimens, 6 species; 
Cystoids toy see ove aie me nee 62 specimens, 6 species; 
Crinoids7tis sais hrc ee: eceetaeae 149 Specimens, 32 species; 
BryOZOans:t. yan theron hore inte tee eet Io specimens, 6 species; 
Brachiopods cece atu ne re 62 specimens, II species; 
Miulluses: ee ir 0) oe eet eee g specimens, 5 species; 
Trilobites2) cate eee. ce ere eee 82 specimens, 9 species; 
The finding of these silicified corals and brachiopods at Lemont 
identical with those occurring in the clay pockets, left little room for 
doubt that the clay and fossils found in it were residual from the 
Niagaran limestone, and that they had been transported to Romeo from 
the Lemont Area. The Romeo quarry is distant about five miles in a 
southwesterly direction from the point near Lemont where the cor- 
responding fossils were found. Both localities are in the valley known 
as the Chicago Outlet, through which the waters which occupied the 
basin of Lake Michigan at the close of the glacial period discharged 
into the Mississippi River. The flow of these waters would have been 
sufficient to transport material like that described from Lemont to 
Romeo, although the period and exact circumstances of this deposition 
have not as yet been determined. The silt-like nature of the deposit 
in the clay pockets shows that it occurred in quiet waters. 
