Upper Devonian Shales. 319 
across the ravine). 'The mass has its longitudinal axis in a 
W. of S. 
_ in other cases I could not determine this point, and am still 
My doubt as to the cause of the inequalities on this lower sur- 
ace. ) 
_ The shale is well characterized by its fauna. Its termination 
18 distinctly marked above by: coarse arenaceous shales an 
sandstone, well known in the Chemung group, but these pecu- 
liar sandstone channel-fillings are not known to occur above or 
low this particular horizon. 
henever, in the neighborhood the outcrop of the shales, 
racteristic fauna was discovered, careful search 
or nine feet. 
The thicker beds were somewhat swollen in the center on 
top, and. wrinkles, looking very much like the shrinkage 
Wrinkles on the surface of a firkin of lard after it has cooled, 
Were seen on the upper surface of these thicker masses. 
The swollen center of these thick masses suggested the ex- 
Planation, i. e., that subsequent to the original deposition of 
the rocks a certain amount of shrinkage took place in 
shales which was not shared by the arenaceous sbannelifilbings 
and thus the margins of the mass were borne. down the 
shrinking shales while the center of the mass, resisting the 
Tesembling impressions of glacier scratches, and the trend of 
