600 CHARLES S. PROSSER 
SECTION ON SLATE RUN 
5. Cuyahoga formation.—Blue, fine-grained sandstones 
and some layers of soft, gray shale which contain but 
little grit. Thin-bedded sandstones with shales and 
shaly sandstones occur at the base, above which are 
shales;contaiming-COnCretionSp cesar ok 
. Gray, argillaceous shale which is very soft and 
gritless, with the exception of a 6-in. compact, gray 
sandstone, the base of which is 3 ft. 2 in. above the 
bottomnof this: Zome..2 0. pee ote ieee ere 
. Sunbury shale-—Thin, black, tough, laminated shale. 
The sharp contact of this shale with the superjacent, 
gray, Cuyahoga shale is finely shown in the bed of the 
run as well as the basal contact at the fall farther 
down stream with the subjacent Berea. The basal 
layer of this shale is arenaceous, strongly pyritiferous, 
and it contains numerous specimens of Lingula melie 
Hall. Different measurements of the thickness of 
thistormation vary, trom 242 to120 ft.3).00) 2... = 
. Berea sandsione——Composed principally of white, 
quartz sand of moderate coarseness, and forms a 
single stratum which varies in thickness from a little 
more than 1 ft. to 5 ft. The upper part contains 
plenty of marcasite and the weathered surface is 
pitted from its disintegration; but the surface is 
horizontal, not undulating. The lower surface is un- 
even and rough, with ridges which correspond to 
the thin sandstones in the underlying Bedford, while 
their faces represent the edges of the layers of soft 
shale, a character that at this locality Professor 
Thomas M. Hills first called to my attention. The 
rapid change in the thickness of this formation and 
the details of its contact with the Bedford formation 
are given more fully in the two following more de- 
tailed sections at this locality. There is no appear- 
ance of concretionary structure in the basal part of 
the Berea and there is a marked line of disconformity 
between the Berea and Bedford formations........ 
. Bedford formation.—Mainly bluish, argillaceous 
shale with an occasional layer of thin sandstone 
from 1 to 1 in. thick. At lower end of cliff with 
overlying Berea sandstone 4 ft. 7 in. to water level. . 
Thickness 
Feet 
26 
5 
43 
Total 
Thickness 
Feet 
69+ 
44-7 
