HURON AND CLEVELAND SHALES OF NORTHERN OHIO 343 
No. THICKNESS Tanne 
Ft. In. Ft. In. 
PEPE LAGKES DAG apres Wiverth slat Ne aictersiats Soca de ts tes 9 9 4 
6. Blue, argillaceous shale, from 202 to 21 in. 
EVI CRG RR aa cheat, ok SOS ip caste SUNY Saal I o— 8 7 
ioe d SHENG) eS oN Cel oe rei ea 8 6 1K) 
AeGraveto bite shale eons Bois ais snow ae eer is 5 4 6 2 
BEE PACKOSH AG serene yeruhns o.sicts cae tus ara 5 ° 5 ite) 
3) A SHRERS 45) TN (Dl sane i eC 2 ie) 
depiacic Shalewto creek level. +... Veeco c on 8 8 
In the region south and east of Norwalk there is generally a zone 
of black shale, like No. 18 of the above section, of variable thickness 
at the top of the Ohio shale, succeeding which, in a few places, is a 
little of the Bedford shale, but more frequently the Berea sandstone. 
This irregular thickness of the upper black-shale zone of the Ohio 
and comparatively little if any of the Bedford formation are due to 
more extensive erosion before the deposition of the Berea sandstone 
than occurred in most of Ohio. At part of the localities studied 
near Norwalk not only is all of the Bedford wanting, but also the 
upper part of the Ohio or Cleveland shale, so that the Berea sand- 
stone rests on the Huron shale. The writer has described a similar 
disconformity between the Berea and Bedford formations in central 
Ohio’ and in northern Ohio from Rocky River west of Cleveland 
eastward as far at least as the Grand River Valley,? except that the 
erosion was not so great as in the Norwalk region. There is an 
example of this disconformity in the immediate vicinity of the 
section described above. In the bed of Vaughn’s Creek and on its 
northern bank a few rods below the Sandusky, Norwalk & Mansfield 
trolley bridge is an outcrop of the Berea sandstone at a lower level 
than the base of the shale section above the bridge. Part of the 
sandstone is very much contorted with more or less concretionary 
structure, while some of it is in fairly regular layers. At places 
there is a bluish, gritty shale below the sandstone and at one point 
the shale is shown to a depth of 5 ft. and is bluish gray and rather 
sandy with thin layers of sandstone in it. It is not certain to which 
formation this shale belongs, although the evidence appears to the 
™ Journal of Geology, XX (October—November, 1912), 585-604. 
2 Geological Survey of Ohio, 4th ser., Bulletin 15 (1912). 
