GEOLOGICAL SCALE OF OHIO. 
Orton, 1895. 
Prosser, 1905. 
Thick- 
ness 
Glacial drift. 
Alluvium and Glacial. 
0-550' 
Upper Barren Coal Measures. 
Dunkard formation. 
525'=*= 
Upper Productive Coal Measures 
Monongahela formation. 
200-250' 
Lower Barem Coal Measures. 
Conemaugh formation. 
400-500' 
Lower Productive Coal Measures 
Allegheny formation. 
165-300' 
Conglomerate Group. 
Pottsville formation. 
250' ± 
Sub-carboniferous limestone. 
Maxville limestone. 
25' ± 
Logan Group. 
Logan formation. 
Black Hand formation. 
100-150' 
50-500' 
Cuyahoga shale. 
Cuyahoga formation. 
150-500' 
Berea Shale. 
Sunbury shale. 
5-30' 
Berea grit. 
Berea grit. 
5-175' 
Bedford shale. 
Bedford Shale. 
50-150' 
f Cleveland shale. 
Ohio shale. \ Erie shale. 
( Huron shale. 
[Cleveland shale. 
Ohio shale, [ Chagrin formation. 
I Huron shale. 
300-2600' 
Olentangy shale. 
Olentangy shale. 
20-35' 
Upper Helderberg or Cornif- 
erous limestone. 
Delaware limestone. 
Columbus limestone. 
30-40' 
110' 
Lower Helderberg limestone, 
or Waterlime. 
Monroe for 
mation. 
[Lucas limestone. 
< Sylvania sandstone. 
[Tymochtee member (?) 
50-600' 
Niagara 
Group. 
Hillsboro sandstone. 
Guelph or Cedarville 
limestone. 
Niagara limestone. 
Niagara shale. 
I 
“Niagara : 
Group.’’ 
Hillsboro sandstone. 
Cedarville limestone. 
Springfield limestone. 
West Union limestone. 
Osgood beds. 
150-350’ 
Clinton limestone. 
Clinton limestone. 
Belfast bed. 
10-50' 
50-150' 
Medina shale. 
Saluda bed. 
20' ± 
Hudson River Group. 
Richmond formation. 
Lorraine formation. 
Eden shale. 
300' ± 
300' 
250' 
Utica shale, not seen in outcrop. 
Trenton limestone. i Trenton limestone. 
130' 
