Cinci/uiati Sibirian Island. — Miller. 8i 
(2) Conglomerates and breccias. — These do exist, the for- 
mer in the basal conglomerate of the Coal Measures outcrop- 
ping in steep escarpments around the margins of the area 
and the latter in the Clinton and Corniferous limestones 
further up upon the flanks of the arch. But the conglomerate 
is composed of pure crsytalline quartz pebbles, which could 
not have been derived from the strata composing a Cincinnati 
island, and the breccias are not confined to the Clinton and 
Corniferous. Limestone pebbles have been found even in the 
lowest Cincinnati limestone upon the very summit of the 
present anticline. 
(3)The same thing may be said of the ripple and wave 
markings. They occur in Ordovician as well as in later strata 
and seem to indicate that shallow seas were not infrequent 
phenomena in this region during all Paleozoic time. 
(4) Plant remains. — The finding in the Clinton of Ohio 
of a supposed trace of land vegetation w'as long taken as con- 
firmation of the "Silurian island hypothesis." Since, however, 
Glyptodendroji eatonense has been proven to be a fragment 
of Ortlwceras, we have only negative evidence there. The 
occurence of silicified wood in the Devonian Black shale at 
different points in Kentucky is as consistent with the sargasso 
sea theory of the shales deposition as shore deposition. One 
would expect to find water-logged timber upon the bottoms of 
sargasso seas. 
Reviewing then the evidence, wo. cannot say indications of 
shallow water and shore conditions are so much more pro- 
nounced in post-Ordovician than in Ordovician strata of the 
Ohio valley, as to warrant the assumption that land first ap- 
peared in this region at the close of Ordovician time and has 
existed continuously there ever since. 
Against this view considerable positive evidence may be 
cited. 
First. — The present arrangement of the drainage contro- 
verts it. It is difificult to understand how two such rivers as 
the Ohio and Kentucky could have established themselves in 
their middle and lower courses squarely across this anticline, 
if the anticline were there first. But granted the antecedent 
character of the rivers and the arrangement is perfectly intelli- 
gible. Extending for 45 or 50 miles somewhat parallel with the 
