3CKEL.1 KENTUC KV. 171 
PORTLAND CEMENT RESOURCES OF KENTUCKY.^ 
Limestones prevailingly low in magnesia and otherwise satisfactory 
s cement materials occur in Kentucky in four different geologic 
groups. These groups, whose areal distribution in Kentucky is shown 
hi the map forming PL VI, are as follows, beginning with the oleic. 1: 
1. Trenton limestone. 
2. Cincinnati group limestones. 
3. Mississippian or Lower. Carboniferous limestone. 
4. Pennsylvania or Coal Measures limestones. 
TRENTON LIMESTONE. 
The Trenton group occupies much of the counties of Franklin, 
jbtt, Bourbon, Woodford, Fayette, Jessamine, and smaller portions 
>f Boyle, Clark, Mercer, Owen, Henry, and Anderson. The lime- 
tones which make up most of this series are usually quite low in 
nagnesia, while their range in lime carbonate is commonly from 90 to 
►5 per cent. 
According to Mr. E. O. Ulrich the rocks in Kentucky that are 
eferred to this group comprise an exposed thickness of about TOO feet 
)f solid, chiefly nonmagnesian, limestone. The magnesian beds are 
jractically contined to the lower 4-00 feet, and it is doubtful if these 
nagnesian beds will reach an aggregate thickness of 150 feet. The 
eries is equivalent to the Mohawkian of New York, to the limestones 
n Middle Tennessee included between the Murfreesboro and Catheys 
imestones (see Columbia folio), and, in a general way, to the u Trenton " 
including Galena) of the Mississippi Valley. 
In Kentucky State reports the series is divided, from below upward, 
fto"Chazy," ''Birdseye," and "Trenton' 1 . The first two are the 
ame as the Stone River group in Tennessee and the High Bridge 
imestone of Campbell in the Richmond folio. The third embraces 
be recognizable equivalents of the Hermitage, Bigby, and Cathey 
imestones of middle Tennessee, and the Lexington limestone (= Her- 
nitage and Bigby), Flanary chert, and lower part of Winchester 
imestone (together = Cathey) of Campbell. 
<rFor most of the data presented in regard to Kentucky cement materials the writer is indebted to 
Ir. E. O. Ulrich, of the U. S. Geological Survey 
