Art, II.] Brownocker, Comiferous Rocks of Ohio 1 5 
In the Taylor and Beil quarries near Marble Cliff the Lower 
or Columbus division is worked to a depth of 60 feet and at 
Delaware the Upper beds are worked to a depth of about 30 
feet. The minimum thickness given by Prof. Orton is 25 feet. 
The thickness must vary considerably, owing to the partial or 
entire removal of the Upper or Delaware beds and also the par- 
tial removal of the Columbus beds. Other things being equal 
the greatest thickness should be found where the upper beds 
are well preserved, as at Delaware. 
THE FAUNAS. 
The faunas herein discussed were collected at the 12 fol- 
lowing points, the location of which may -be noted on the ac- 
companying map. PI. II., — (i) Deer Creek, (2) Harrisburg, (3) 
Columbus, (4) Marble Cliff, (5) Dublin, (6) Delaware, (7) Rad- 
nor, (8) Marion, (9) Sandusky, (10) Kelley’s Island, (ii) White 
House, (12) Bellefontaine. 
The faunas are rich and varied. Almost everywhere the 
strata contain abundant fossils. However, the Lower or Co- 
lumbus beds are much superior in this respect. The faunas 
range from protozoans to vertebrates, though the latter are not 
considered in this paper. All branches of the animal kingdom 
have one or more representatives, veftnes excepted. The coel- 
enterata, mollusca, and molluscoidea especially are well repre- 
sented. 
In the discussion of the faunas the order from south to 
north will be followed, except in the case of Marble Cliff which 
will be considered first. The latter fauna has been collected 
with more care than any other, and hence will be used as a ba- 
sis for comparison. 
The Marble Cliff Faunas. These were collected in Price’s 
quarry where the Columbus beds are worked to a depth of more 
than 30 feet. Above them the Delaware beds are represented 
by a maximum exposure of 12 feet of shales. 
A section of the Lower horizon at this point is shown Qn 
Plate III. For convience the workmen’s nomenclaturig is 
used. This in most cases is self-explanatory, but sQm!etime3 
