and Onondaga Salt Group of the Iowa Report. 47 
out any regular lines of bedding or stratification, but presenting 
planes of cleavage or false stratification at every conceivable 
angle to the horizon. It possesses a porous or vesicular structure, 
resulting mainly from the decomposition of its numerous fossils, 
and has an ashy gray color inclining to buff. At Bridgeport the 
rock contains casts of Caryocrinus ornatus, Ichthyocrinus levis, 
Hucalyptocrinus decorus and Myalina mytiliformis in abundance, 
clearly <a 8 ne nee to be the same as the Niagara Group 
of the “gel York s 
During the past San we have revisited the localities on the 
Wedel, i, and at the lime kiln quarries just above Port Byron, 
we = 
na is dg sal Petar like P. galeatus and three ot four 
species of shainbered shells belonging to the genera Orthoceras 
and Cyrtoceras, common to both localities. Indeed on placing 
the fossils from Bridgeport and Port Byron together, it seems to 
us that no palsontologist could resist the conviction that the 
beds at these localities belong to the same horizon. The fact 
that the crinoids of Bridgeport have not been found at the other 
localities does not appear to us to militate greatly against the 
— to which we arrive in relation to = equivalence of 
the beds, inasmuch as this class of fossils is more generally 
restricted to certain localities from the :etegttons habits of these 
animals, than the Mollusca and the 
The evenly bedded limestones whiel Prof Hall refers to the 
age of the Onondaga Salt Group, although appearing in co: 
erable force on the Iowa shore, have not yet been met rine = “4 
ois, and they appear to be intercalated in the irregular bed 
portions of the mass, instead of — distinct from, and ann 
Ing the same, as he su upposed. They appear at two localities on 
the west side of the river, oné exposure near the centre of 
ea tere te of the Niagara Limestone as it appears in 
Northern Illinois and Iowa, and oe to the arch of 
Prof. J.D pane du (see Vol. i, Part 1, Geo 
