264 GEOLOGY OF OHIO. 
out Peru township, and especially in the banks of Alum Creek, make it 
evident that the underlying Erie shale, if it exists at all, must be re- 
duced to a few feet in thickness. The absence, then, of the Hrie shale, 
or its great attenuation, makes it uncertain whether the above exposure 
may not belong to the Huron. It bears a resemblance to some portions 
of the Huron. In the absence of fossils, 1t will be necessary to leave its 
designation conjectural. 
The Erie Shale-—The existence of this shale in Morrow county is 
altogether hypothetical. The most southern point at which it has been 
observed is in Polk township, in Crawford county. It is not known to 
exist in Delaware county, which lies next south of Morrow, but it may 
have the thickness there of a few feet. This horizon, owing to its shaly 
character, is generally deeply buried under the Drift. On the accompa- 
nying map this shale is represented as running out, but the evidence to 
that effect is not conclusive. 
Huron Shale.-—This shale underlies the western tier of townships, its 
eastern limit leaving the county near the south-west corner of Benning- 
ton township and the north-west corner of Washington township. It 
is well exposed at a number of places, especially along the valley of the 
Kast Branch of the Olentangy, in Westfield and Cardington townships, 
and along Alum Creek, in Peru township. The exposure at Cardington 
amounts to about twenty feet. It is here in very thin beds (J, to } of an 
inch), and parts, under the weather, into small chips. When wet it has 
no unctuous feel, but keeps its color and texture. It is rather firm, and 
of a black color. It contains no concretions, or hard masses. An in- 
erustation of alum forms on the exposed edges of the beds, but very little 
pyrites can be seen. The beds have a slight dip east. 
The black slate, or Huron shale, is exposed in the banks of the creek 
on lot 13, landof Annis Oliver, and at other points below. At Benedict’s 
mill, lot 16, twenty feet may be seen. It is here, also, of a very homo- 
geneous character, like that at Cardington. 
This exposure is approximately forty feet below that at South Woodbury. 
At West Liberty the following section, in descending order, may be seen: 
Nios iby Met ardep ani rite ii. eu ce aie a csutie disco ail ereayee mNn e a ete 2D) ith 
Ch LNTATANGLELG deaneu cee atnete an tu venteies mstaaieh aisles os slo etoustinen er eieeiee Seperate @B 
‘¢ 3. Blue, silicious limestone, like that at South Woodbury. In 
OWNED Civecie ra. wicscm cle teinees wales cela tecleteacn tn atseeeerrete te oneal mtannentes 4 in. 
of AL, MRawbay Nao rmavoyeferaverOWlss SHANUS) saad soosec-oob5Gad00 Ga0bdd 60000 45600 OODDN0ES aid) 
POtAD o.c. Sandee ve ae se octemacalsaituee silva ala ctene a sone ure mettertactseatettspee 56 ft. 4 in. 
Along Alum Creek, about half a mile north of the county line, the 
Huron shale is well exposed. Indeed, there is nearly a constant exposure 
of the black slate along that creek south from South Woodbury to the 
