PLATE I. 



Dakota sandstone resting on Permian shales. Man's head in line with 

 contact. Spring creek, six miles north of Washington. 



Unconformity of Pleistocene on Permian. Ravine running from left 

 to right in Permian shales with thin limestone forming the top crosses 

 a buried gully at right angles to it filled with Pleistocene material, 

 which is etching backward. Note the tipping of the limestone into 

 the old gully (undisturbed by recent erosion). About three miles east 

 of Washington. 



