Yol. 54.] EOCKS iJJD FOSSILS FROM FRANZ JOSEF LAND. 647 



I. 



Per cent. 



SiO^ 47-28 



TiOa 1-48 



Al.,03 13-24 



Fe„03 4-44'i 



FeO 10-50; 



MnO -40 



OaO 11-04 



MgO 5-94 



K^O -31 



NaaO 2-62 



Loss on ignition 2*00 



II. 



Per cent. 

 47-07 



IIT. 



Per cent. 

 47-48 



12-96 



13-75 



16-65 



17-47 



11-27 



9-50 



-58 



1-97 



11 -k 



6-47 



•60 



2-89 



100-00 



100-00 



99-25 



The two analyses of rocks from Iceland are by Eunsen/ but 

 they are quoted from Roth's ^ Gesteins-Analysen.' They are 

 selected from eight other analyses of ' normal pyroxenic rocks,' 

 which vary within the limits indicated in the following table : — 



Minimum Maximum 



Per cent. Per cent. 



SiO., 47-07 50-25 



AlA 12-55 18-78 



FeO 11-69 19-43 



CaO 11-10 13-01 



MgO 5-20 9-50 



K,0 0-20 0-60 



Na^O 1-24 2-92 



It is much to be regretted that we have no recent analyses of 

 the basalts of the Brito -Arctic province, but we may safely conclude, 

 from those quoted above, that the rock from Cape Flora represents 

 a very widely-distributed type. 



In our previous paper we called attention to the widespread 

 evidence of silicification. The collection now under consideration 

 includes many specimens which illustrate this point. Quartz, 

 chalcedony, agate, laminated siliceous deposits containing plant- 

 remains and silicified wood, are all represented. In view of the 

 occurrence of geysers in the basaltic region of Iceland, one is 

 naturally led to ask whether some of these siliceous deposits may 

 not indicate the former presence of hot siliceous springs in Franz 

 Josef Land. 



Additional specimens of the zeolites, analcime and natrolite, 

 have been received, and among them occur some black crystalline 

 groups of analcime found in a mass of lignite which was associated 

 with the second tier of basalts at Cape Flora. The crystals have 

 evidently grown in the vegetable matter, and their peculiar black 

 colour is due to inclusions of a carbonaceous substance. 



Further specimens of radiolarian chert have been found. They 

 occur as pebbles in a calcareous sandstone of Jurassic age, from 

 Cape Gertrude. Their presence under these circumstances strengthens 



^ Pogg. Annalen, vol. Ixxxiii (1851) p. 202. 



