ONONDAGA SALT GROUP. 
119 
44 . 
f. Terminal mass of the deposit, which is a light grey or drab-colored impure limestone, with cavities sometimes con¬ 
taining crystals, and often embracing shaly beds. 
c, d, e. Shaly and compact impure limestones, with shale and marl, embracing two ranges of plaster beds. Between the 
two ranges of plaster beds is a bed of shaly limestone, d. with some imperfect hopper-shaped cavities, and a 
harder grey limestone, with numerous pores, sometimes very minute. 
b. Green marl and shale, with some shaly limestone, containing veins of fibrous gypsum, selenite, and small nodules of 
gypsum. 
a. Green and bluish green shale, with bands of red. 
There are no well marked lines of division between the different portions of the deposit as 
here enumerated, but each one taken as a whole is sufficiently well characterized. 
1. The red shale forming the lower division of the group, and so well developed in the 
Third District, I have not been able to find west of the Genesee river. It appears in the 
eastern part of Wayne county, as indicated by the deep red color of the soil which overlies 
it. At Lockville the greenish blue marl with bands of red has been quarried from the bed 
of the canal. 
West of the Genesee this is the lowest visible mass ; the red shale has either thinned out 
or lost its color, gradually becoming a blueish green ; while otherwise the lithological cha¬ 
racter remains the same. On first exposure it is compact and brittle, presenting an earthy 
fracture ; but a few days are sufficient to commence the work of destruction, which goes on 
till the whole is resolved into a clayey mass. 
Since a deoxidation of the coloring matter of the red shale would produce the green color 
of the lower mass as developed in the Fourth District, it is, perhaps, not improbable that this 
cause has operated on a large scale, changing the color of the mass by the same process 
which has produced the green spots and bands in the same rock farther east. 
The green marl of the lower division appears near the canal at Fairport, and again at Car- 
tersville. On the west side of the Genesee this portion appears on the surface in but few 
places. The bed of the stream at Churchville exposes the greenish blue marl, and in dig¬ 
ging a well at the same place this was found at a depth of thirty feet below the surface. 
About one mile southeast of Churchville, at Wiley’s mills, the green marl is seen in the bed 
of the stream. At this place it embraces one or two thin strata of impure drab-colored lime¬ 
stone. These localities are near the northern margin of the formation, the limestone being 
