EXPLANATION OF PLATE 27 



Fig. 1. A col and a but on the contact between Chico and Basement Complex 

 between Williams and Harding canons. The but on the left is composed of resistant 

 gray Chico conglomerate while the col has been formed in the weathered, red 

 conglomerate. The complex is shown on the extreme right. These cols and 

 buts are characteristic features of the contact between the Chico and the 

 Basement Complex. 



Fig. 2. Stream terraces, Santiago Canon. Viewed from a point on Santiago 

 Creek one-half mile upstream from Williams Canon. The highest terrace is the 

 divide between Silverado and Santiago canons. The hill on the left consists of 

 westward dipping Vaqueros sandstone, while the slopes on the extreme right are 

 composed of Chico sandstones and shales. 



[2741 



