Plate 21 



View of mouth of Darkroom cave and adjacent wall from a photograph taken from the 

 lake^ce on October 23 1909. At a in the kft upper portion we may see horizontal 

 Sensides The faul 'plane,' on which the cave was cut, shows a ^'S^t downthrow on 

 the riKht. The wall at the right shows for the greater part a surface produced by differential 

 solution. 



