142 
Frank Carney 
inconstancy of these details as we pass vertically through a succes- 
sion of formations shows whether the land area furnishing the 
sediments is gradually rising from the sea or is being transgressed' J 
by it, and indicates also the stage of the erosion-cycle as well as i 
the general climatic conditions. But the organisms of the pasti ; 
periods, and equally too of the present, constitute the vitalizingi 
fact of geologic studies, and at once furnish the basis for geography, i 
either past or present. | 
Fig. 7. The slumping of mud sediments in the Bedford along Rocky Fork, 
Franklin Co., just west of Professor Prosser’s “conspicuous tree” section (Journal j; 
of Geology, vol. x, 1902, pp. 277-278); the slumping occurred while the mud was | 
fresh; sediments were then deposited over the distorted zone, and the river has 
recently brought it to view by undercutting the shales. 
This consideration accounts for the following brief discussion of 
the sediments and associated conditions indicated by the forma- 
tions studied in Mary Ann township; and since these formations 
belong to the Mississippian and Pennsylvanian periods, I have 
included in the discussion all of the former period as exhibited in 
central Ohio. 
(2) The Bedford Shale formation save in its uppeimost few 
feet is a fairly homogeneous mud deposit. It varies somewhat 
from place to place in color, the range being from chocolate red 
to a blackish gray. The texture of this formation suggests off- 
