18 
Aug. F, Foerste 
westward as far as Boyle county^ in Kentucky. West of this 
line of outcrop, the Paint Lick member apparently is replaced by 
more fossiliferous strata, but where it is characteristically devel- 
oped, the overlying Mount Hope and Fairmount faunas are in 
striking contrast with the underlying Eden faunas. This con- 
trast is greatest southward, in Madison, Garrard, Lincoln, and 
Boyle counties, where that part of the Eden below the Paint Lick 
horizon was grouped under the term Million, on account of its 
different faunal expression from that exhibited by the Eden at 
Cincinnati. At Cincinnati, however, where the typical Paint 
Lick member is absent, the McMicken member bridges, in part, 
the faunal break. 
Moreover, the central and southern Kentucky representatives 
of the Mount Hope and Fairmount members at Cincinnati belong 
to the southern or Maury phase of the Fairview division of the 
Maysville. This is another reason why the contrast between the 
faunas above and below the Paint Lick horizon appears greatest 
southward, where the intermingling of faunas was least possible. 
Another important, practically unfossiliferous, argillaceous sec- 
tion is that represented by the Tate member, between the Fair- 
view and AIcMillan divisions of the Alaysville. This may be 
traced all the way from Casey and Boyle counties, in central 
Kentucky, to Adams county, in Ohio. In this case the greatest 
contrast between the overlying and underlying faunas again is 
seen farther southward, in Madison, Garrard, Lincoln, Boyle, and 
Marion counties, while at Cincinnati the contrast is considerable, 
but not as striking. Moreover, in the counties of central Ken- 
tucky just named, that part of the McMillan section which over- 
lies the Tate member consists chiefly of dove-colored limestone 
layers, which are in rather striking contrast lithologically with 
the stratigraphically equivalent strata northward. For this part 
of the McMillan section, in central Kentucky, the term Gilbert 
member has been adopted. Stratigraphically it corresponds most 
nearly to the Corryville member northward. 
Another argillaceous horizon forms the lower half of the Arn- 
heim, and has been called the Sunset division of the latter. This 
horizon can be recognized most readily between Adams county, 
in Ohio, and Stanford, in Lincoln county, Kentucky. North- 
ward, this lower, or Sunset division of the Arnheim, is moderately 
fossiliferous, but between the southern margin of Clark county 
