DISTRIBUTION OF THE SANDSTONE DIKES. 



413 



below the general level, and exposed numerous sandstone .dikes. The north- 

 ernmost exposures of these dikes are along the North fork of Cottonwood 

 creek ; thence they continue in a belt southwestwardly across Crow and 

 Squaw creeks, Roaring river, Middle fork, Dry creek, and Salt creek, nearly 

 to Cold fork, occurring in an elliptical area about eighteen miles long and 

 six miles in average width. 



The distribution of these dikes is illustrated upon the accompanying map, 

 figure 2. Only those dikes which are 18 inches or more in thickness are 













. <t 



COAST RANGE 

 METAMOR PH IC 



MORSETOWN & CHICO 

 CONG.SS.aSHALCS 



SANDSTONE DIKES 



NEWER FORMATIONS 

 OF SACRAM.VALLEY 



l-y^T^L'-i 



Scale of Miles 



Figure 2. — Map of the Sandstone Dike District. 



Only those dikes which are 18 inches or more in thickness are represented. The serial num- 

 bers, some of which are omitted, designate localities. 



represented. For convenience of reference, the localities of dike exposures 

 are numbered ; but on account of the small scale of the map some of the 



