PLATE II. 
Bul. 502, U. S. Dept. of Agriculture. 
e 
Sr i ae ae 
an 
SSAee! 
SHOWING NEARLY VERTICAL CLEAVAGE PLANES. 
Fic. 1.—SIDE OF AN IRRIGATION DITCH 
Fia. 2.—SHALES HAVING NEARLY HORIZONTAL LAYERS WHICH HAVE BEEN CUT BY 
CLEAVAGE PLANES CAUSED BY GREAT PRESSURE. 
k strata. 
rvening roc 
te 
yers and in 
> 
uw 
Cleavage planes continuous through shale l 
