UNCONFORM 



'ic has reason to suspect the existence 

 of such a structure 



An extreme case presents little difficulty. It can be 



expressed so dearly upon a map as at once to tell its 



own stor\ 28 the sheet of rock // 



is a flat unconformable cake lying upon 



ed and denuded strata. >n across this 



cake would disclose an abrupt junction of the horizontal 



beds on the edges of the steep and vertical series. Hut 



many cases occur where the discordance between t he 



two series is far less strong, where indeed much care and 



labour may be required to make out an unconformabiliiy 



at all. 1 -or iu-rc B| the case of faults, the actual 



contact between two groups of rocks is compara 



m seen. We must usually fa 



dip and strike and their lithological characters whether 

 : they are separated by an unconformability. In 

 the diagram we have already used so much (Fig. 28) 

 another and less violent unconformability is shown 

 towards the north-west corner, where the series of beds 

 A' steals over the denuded outcrops of the series / 



A special interest attaches to unconformabil 

 inasmuch as they enable the geologist to recover the 

 land surfaces of former periods. Some wonderful ex- 

 amples of >n of ancient topography are to 

 be met with in the west of the counties of Ross and 

 i, where groups of mountains, older than the 

 he fossiliferous formations of Britain, once 

 cd sandstone and conglomerate, 



are now in course of being once more laid bare by the 

 denudation of the younger unconformable formation 



