HURON AND CLEVELAND SHALES OF NORTHERN OHIO 341 
cone-in-cone structure occur at least in the lower part of the Ohio 
shale, as for example in ‘‘the Narrows”’ and other glens north of 
Worthington. In the general section of Huron River and Slate 
Run large spherical concretions occur in the lower part of the 
highest thick zone of black shale as well as in all the lower zones of 
black shale with a thickness of 8 ft. or more. It appears certain, 
therefore, that all of the rocks composing this section belong in the 
Huron shale. This section perhaps does not include the highest 
black shale seen on the Huron River in the southwestern corner of 
Peru Township in which nothing was seen to show whether it 
belongs in the Cleveland or the Huron shale. This general section 
does not extend to the base of the Huron shale, which is shown in 
Slate Cut on the Lake Shore & Michigan Southern Ry. some 7? 
miles north of the cliff just above Milan, where the lowest outcrops 
of the Huron shale on Huron River are shown. The general section 
gives 178 ft. of the Huron shale on Slate Run and Huron River and 
the thickness of the mostly covered interval from the lowest 
outcrops of the section to the base of the formation in Slate Cut is 
not known. If to the 178 ft. of Huron shale in the general section 
the thickness of the interval to the base of the formation be added, 
it will certainly give a thickness of over 200 ft. for the Huron shale 
on the Huron River. Dr. Kindle estimated that “the Huron will 
have in the Huron section a thickness of probably too feet." A 
thickness of over 200 ft. for the Huron shale is corroborated by the 
record of the Citizens’ Well, No. 1 at Norwalk, about 5 miles east 
of Monroeville. The well is located by the side of the Wabash 
R.R. just east of the Norwalk Gas Plant and its mouth is 40 ft. 
higher than the level of East Fork Huron River at the old water- 
works. The first 85 ft. of the well was in drift,? and the Prout 
limestone which directly underlies the Huron shale in this region 
was reached at a depth of 288 ft. according to the writer’s notes. 
From a study of the outcrops in the vicinity of Norwalk it appears 
that the black shale struck in this well at a depth of 85 ft. is strati- 
' Tbid., p. 199. 
2 Dr. Stauffer in his record of this well gives only 76 ft., composed of samples Nos. 
1-5, as drift (Geological Survey of Ohio, 4th ser., Bulletin 10 [1909], p. 117); but in the 
writer’s notes on an examination of the samples made on September 11, 1905 he gave 
samples Nos. 1-6 as drift. 
