THE CAMBRIAN PERIOD 



477 



Fig. 358. Map showing the Upper Cambrian formations. The outcrops 

 are shown in black. The continuous lines represent areas where the 

 Upper Cambrian formations are confidently believed to exist, though 

 concealed. The dashes represent areas where there is some reason for 

 believing them to exist. The dotted areas represent areas from which 

 the Upper Cambrian is believed to have been removed by erosion. The 

 unshaded areas have the same meaning as in Fig. 357. 



