OUTLINES OF GEOLOGY. 



43 



and particularly the neighbourhood of the Dead £ea, show 

 many traces of volcanic action. Active volcanoes have been 

 seen within historic times in the Morea ; the volcanic charac- 

 ter of Naples and Sicily is well known ; and although no 

 active volcanoes are now found in Spain and Portugal, volcanic 

 rocks and minerals abound, and earthquakes are occasion- 

 ally felt. The line which passes through the last named 

 regions, strikes the Azores, which are of volcanic origin. 

 Besides these great volcanic systems we may mention the 

 volcanic groups of the Canaries and Madeira, and the vol- 

 canic island of Iceland. 



Volcanic action is, however, most active in changing the 

 face of the globe in the tropical regions of Polynesia. The 

 numerous archipelagos which here exist may be ascribed to 

 the joint action of volcanic fire and the coralline animals, and 

 the islands are to be seen in every stage of formation, from 

 dates as old as the diluvium, or, perhaps, as ths most recent 

 of the ancient formations, until we find them rising from the 

 sea before the eyes of the existing generation. 



II. ANCIENT FORMATIONS. 



Stratified, 



I. SUPERIOR ORDER. 



Supercretaceous Groupe, Delabeche ; Terraines Yzemeniens TTialassiques % 

 Brogniart. Tertiary Formations. 



92. The formations of this order have been but lately 

 known to geologists. From the general looseness of their 

 aggregation, except when in the form of calcareous concre- 

 tions, they were supposed to be of modern origin, and from 

 the low level at which those first studied were found, they 

 were considered as merely alluvial. These views were, for 

 a time, supported by the analogy of their organic remains to 

 those at present living, but more close study showed, that 



