50 
MUSEUM BULLETIN NO. 2S. 
symmetrical type of ripple-mark in this formation. A specimen 
of Berea sandstone ripple-mark presented to the Geological 
Survey by Prof. Prosser shows rounded crests and troughs with 
an amplitude of 2f to 3| inches and maximum elevation of crests 
of one-fourth inch. It appears safe to conclude in view of the 
absence of asymmetrical ripple-mark in the Berea that it rep- 
resents a lacustrine deposit. Some of Prof. Prosser's 1 careful 
descriptions of the ripple-mark and closely associated sun- 
cracks in this horizon can only be interpreted as indicating very 
shallow water in this lake which at times over the shallower parts 
entirely disappeared. Prosser states: ‘‘The coarser layers of 
sandstone have numerous examples of small ripple-marks with the 
crests from I to 2 inches apart. The shale shows splendid 
examples of sun-cracks, extending almost to the very base of the 
zone, some of which have fillings an inch in width.” Ripple- 
marks with an amplitude of 1 inch would certainly indicate 
water not many inches in depth (see page 28.) while the sun 
cracks, of course, show temporary desiccation. This association 
of ripple-mark of small amplitude and mud-crack in the same set 
of beds confirms the inference of very shallow water conditions, 
an inference that would be drawn from the ripple-mark alone. 
The evidence for the lacustrine or continental origin of the 
Berea sandstone furnished by the fossils, though somewhat 
inconclusive when taken alone, points toward their non-marine 
origin. Several fragments of fish remains have been found in 
some of the Berea sandstone quarries. These afford little or no 
evidence regarding their affinities to marine or freshwater types. 
Other fossils are unknown in it in Ohio, although its supposed 
equivalent, the Cory sandstone of Pennsylvania, carries a marine 
fauna of Pennsylvanian age. The absence of invertebrate 
fossils from this horizon in Ohio is itself evidence of some bar to 
their existence in the waters in which the Berea sandstone was 
laid down and the evidence of the ripple-mark leads to the con- 
clusion that this bar was the fresh water of a shallow lake. 
The Berea sandstone is considered by Girty, Prosser, Kindle, and 
others to represent the initial formation of the Carboniferous in 
1 Bull. GeoL Suit., Ohio, No. 15, pp. 250, 266-7. 
