THE SILURIAN PERIOD 



111 



The faunas of these two provinces show greater differences than 

 does the northern province as compared with North America, or 

 even other continents. This implies a lack of free communication 

 between the southern European province and the more typical 

 Silurian provinces of the earth. 



As in America, European Silurian strata are largely concealed 

 beneath later formations. Usually the Silurian rests conformably 



Fig. 61 



Sketch map showing the relations of land and water in Europe 

 during Silurian time. Dotted areas, water. (Slightly modified 

 after De Lapparent.) 



upon the Ordovician, except in the British Isles. Also in most of 

 Europe the transition to the Devonian was gradual, except in the 

 British Isles, where the Silurian strata were tilted and eroded before 

 the deposition of the Devonian. In much of the southern province 

 the rocks are folded and tilted, though this deformation took place 

 sometime after the close of the Silurian. In mid-Silurian, as in 

 North America, much limestone was formed across the British 

 Isles, southern Scandinavia, and well into Russia. Silurian strata 



