STATE GEOLOGIST. 27 
Depth to top 
Thickness. of formation 
Feet. in feet. 
AMOS ATM EStONG! «are os cieteciocod vienie ecslae be e's 1 285 
HIESCE COW CUM e SAN Cacesan actor acs se sicrs eee ese 5 385 
Cambridge limestone’ <2. 2.2.5. 205.-0+00% 4 411 
DumkandesandeCS0 0-00) vata ches ecrerciens 95 530 
Macksburg 500-foot sand.................. 22 702 
The Dunkard or 300-foot sand is quite generally regarded as the 
equivalent of the Mahoning. That this cannot be correct is shown by the 
following partial section of the Hocking Valley coal field.* 
Thickness 
in feet. 
Cambridge slimestone | oo si ee «oie Here hE a Soe ie Sieieteles 2-10 
Mahoning sandstone, upper division................. 50 
BrisheCreekxcoals (NOs 0G)! srs ee ooo eee wile eee erehars 2% 
Brusht Creeks limestone voteee sesss eo gltee e caters aretes 4 
Mahoning sandstone, lower division................. 15-25 
WippersHree pOrts.CO alec is oes coors: eestor ohes Shel aecoke «elbncuays 0- 3 
CT Ay aerate rise Ee retest tlaba nerousdbe tif coiee 
Wppenghreenonrt V7 SHALES io. cc50: is ciescee ole se bora e cele s nie 35 
Limestone and sandstone........ 
. Middle” kittanine coal ACNO: 26) 2.5.2... cies sce nce esse 5-13 
This shows the Mahoning sandstone lying immediately below the 
Cambridge lime, but experience in the field demonstrates that the two are 
not ordinarily in contact. Measuring from the base of the lime rock to 
that of the Mahoning, an interval of 76 feet is found, while, according 
to the records in the Dunn well, the interval is 210 feet. A divergence of 
this sort cannot be explained by assuming that the section expands east- 
ward, for a study of the relative positions of the Pittsburg coal, the 
Ames and Cambridge limestones farther west with the same formations 
near Macksburg, shows no material change, and it is certainly unreason- 
able to assume that the formations just below the Cambridge limestone 
expand at anything like the rate that would be necessary to make the 
interval which this nomenclature requires. Further, naming the sand in 
question the Mahoning makes impossible a rational classification of the 
lower formations. The position of the sand with reference to the Cam- 
bridge lime is that of the Upper Freeport. 
The positions of sands 3 and 4 are shown by the record of Centen- 
nial Well No. 7, at Cow Run. The well head is at the horizon of the 
Meigs Creek coal. ; 
Depth to top 
Thickness. of formation 
Feet. in feet. 
PittshiuneecoalesGNoss8)) acco seeccks wcpo ene elses s shes 1 116 
Mitch ellesan dee ses ie aie ese sene wale bueiehh beers 25 205 
Red shales (“Big Red’’).............00000. 80 235 
First Cow Run sand..:.:........ Bag ee ahccthe 32 423 
1Geol. Sur. of Ohio, Vol. V, p. 918. 
