Prof. A, E. NordensJciold — Geology of Spitzbergen. 63 



Thus, in those portions of Northern Europe which have been best 

 studied by geologists, there is ample proof that the three periods of 

 the Lower Silurian, of the Upper Palaeozoic (extending from the 

 Devonian to the Permian), and of the Miocene, were all marked by 

 the most violent outbursts of volcanic forces ; while in the intermedi- 

 ate periods few, if any, traces of such action can be discovered. But 

 when we pass to other areas, we find the most violent outbursts 

 taking place in what are with us periods of quiescence, and vice versa. 

 Nothing is more certain than that, during the middle portion of the 

 Tertiary period, the districts of Western Europe must have been the 

 scene of volcanic violence, on a scale perhaps far surpassing what is 

 now seen in South America or the Indian Archipelago ; and that 

 ever since that period a gradual decline of the volcanic forces has 

 been taking place in our area. 



Seeing, then, that it is absolutely certain that in a district long 

 unmarked by volcanic disturbances these powerful subterranean 

 agencies may make their appearance, gradually attain their climax, 

 and then die away, the following questions present themselves as 

 being of the greatest interest to the geologist : What are the circum- 

 stances and attendant phenomena which mark the first appearance of 

 volcanic activity in an area hitherto quiescent ? What are the several 

 stages through which the manifestation of igneous forces successively 

 passes in reaching its climax ? And what are the symptoms that 

 work their gradual decline and extinction ? 



With these there presents itself another problem, namely, that of 

 the relation of the violent actions attending volcanic outbursts to the 

 perhaps equally powerful, but more slow and extended, movements 

 which take place in adjacent areas not exhibiting any manifestations 

 of the volcanic phenomena. 



On all these questions we think important light is thrown by the 



study of the volcanic rocks of Central and Southern Europe, and of their 



relations to the great central rock masses of the Alpine system ; and 



to these we shall proceed to direct attention in subsequent chapters. 



{To he continued in our next Number.) 



III. — Sketch of the Geology of Ice Sound and Bell Sound, 



Spitzbeegen. 



By Professor A. E. JSTordenskiold, of Stockholm. 



Part II. 



[Continued from the January Number^ page 23.) 



THE Fossil Plants from Bear Island have been described by 

 Prof. Oswald Heer ; there are 18 species (see Quart. Journ. Geol. 

 Soc. Lond. 1872, vol. xxviii. pp. 161-173. pi. iv.), namely : — 



1. Calamites radiatus, Brgn. 



2. Cardiopteris frondosa, Goepp. sp. 

 3. polymorpha, Groepp. sp. 



4. FalcBoj^teris Roemeriana, Goepp. sp. 



5. Sphenopteris Schimperi, Goepp. 



6. Lepidodendron Veltheimianum, Sternb. 

 7. commutatum, Scliimp. 



8. Carnegyianum, Heer. 



9. Wijkianwn, Heer, 



10. Lepidophyllum Moemeri, Heer. 



11. Knorria imbricata^ Sternb. 



12. acicularis, Goepp. 



13. Cyclostigma Kiltorkense, Haught. 

 14. oninutum, Haught. 



15. Halonia tuberculosa , Brgn. ? 



16. Stigmaria ficoides^ Sternb. 



17. Cardiocarpumpunctatiim, Goepp. et 



Berg. 



18. Cardiocarpum ursinum^ Heer. 



