EXPLANATION OF PLATE 44 



Fig. 1. Looking north at Planicosta Butte, a plateau remnant a mile 

 south of Merced Falls. Steeply inclined Mariposa slates are seen in the 

 foreground. The hill is capped by coarse sandstone which yielded an 

 abundance of Venerioardia planicosta merriami. 



Fig. 2. Clays of the lone formation along the Merced River one mile 

 southwest of Merced Falls capped by a stratum of andesitic tuff breccia. 

 These clay beds are stratigraphically below the sandstones of Planicosta 

 Butte shown in the figure above. 



[520] 



