404 



GEOLOGY 



a doubly plunging anticline; that is, an anticline the axis of which 

 dips down at either end. Fig. 320 shows a combination of syn- 



-L J. J_ 



V 



h 



-r T T 



Fig. 319. Map record of dip and strike showing plunging (dipping down at 



ends) anticline. 



clines and anticlines, and Fig. 321 a cross-section along the line ab 

 of Fig. 320. The outcrops of rock where the dip and strike can be 



Fig. 320. Map record of dip and strike showing complex structure. 



determined may be few and far between, but when they are suffi- 

 ciently near one another, the structure of the rock, as shown in 

 Fig. 320, may be worked out, even though the surface is flat . 



Fig. 321. Cross-section of Fig. 320, along the line ab. 



