412 



GEOLOGY. 



and France. Aside from these larger areas, the Devonian is known 

 in limited exposures at many points in the mountains of central and 

 western Europe, in Germany, France, Austria, Hungary, Switzerland, 

 Spain, Portugal, and Turkey. As a result of folding and faulting, the 



Fig. 202. — Sketch map of Europe during the Devonian. The horizontal lines repre- 

 sent the Lower Devonian ; the vertical lines mark the additional areas where 

 the Middle Devonian occurs. (After de Lapparent.) 



structure of the system is often very complex, 

 complex structure are shown in Figs. 203, 204, 



The Lower Devonian is often conformable 

 where the Lower Devonian is absent, and the 

 latter rests unconformably on the Silurian, or on 

 which may happen to serve as its base. This is 

 Cambrian in Belgium and northern France. 



The areas where the Devonian beds outcrop 

 indication of their actual area, for they are to a 

 The Devonian strata exposed in various parts of 



Illustrations of the 



and 205. 



on the Silurian, but 

 Middle present, the 

 any other formation 

 its relation to the 



are by no means an 

 large extent buried. 

 Russia are probably 



