402 PETROLOGICAL ABSTRACTS AND REVIEWS 



tions. SchoUer's akermanite could not be prepared, but 5Ca0.2Mg0.6Si02 .. 

 and 2CaO.Mg0.2Si02 were recognized for the first time. The tridymite- I 

 cristobalite inversion temperature is essentially 1470° C, but measured with 

 difiiculty because of the great sluggishness of the inversion. 



Ferguson, J. B. "The Oxidation of Lava by Steam," Jour. 

 Washington Acad. Sci., IX (19 19), 539-46. 

 Demonstrates experimentally that the formerly generally supposed oxidiz- 

 ing power of steam in lavas is not effective. Hence volcanoes may give ofif 

 lava bearing ferrous iron and yet discharge large amounts of steam. 



Florke, Wilhelm: tjber die kunstliche Verwitterung von Silikat- 

 gesteinen unter dem Enfiuss von schwefliger Sdure. Giessen, 

 1915. Pp. 32. 



This is a study of the action of sulphur dioxide on coarse-grained igneous 

 rocks. Experiments were carried on in the presence of water. All types of 

 rock, varying from granite to gabbro, were attacked by the SO2 vapors. The 

 ferro-magnesian minerals were most corroded, hence the basic rocks also suf- 

 fered most. Soluble sulphates of aluminum, iron, manganese, calcium, 

 magnesium, sodium, and potassium were produced, as well as insoluble hydrox- 

 ides of aluminum and iron, 



FoYE, Wilbur Garland: " Geological Observations in Fiji," Proc. 

 Amer. Acad. Arts and Sci., No. i, LIV (1918), 1-145, bibli- 

 ography, figs. 40, pis. I ; in two parts. 

 A summary of the geology and petrology of the Fiji Islands is here presented. 

 The group consists of two larger islands, Viti Levu and Vanua Levu, having 

 central cores of deeply eroded plutonic rocks and possibly representing an earher 

 continental mass, and of several smaller fringing land masses. Four periods 

 of vulcanism are recognized, the first being rhyolitic, the last basaltic, and the 

 two intermediate ones andesitic. On Viti Levu a series of Miocene ( ?) sedi- 

 ments is much folded and overlain on the coastal plains by gently dipping post- 

 Tertiary beds. On Vanua Levu are Pleistocene or recent coastal plain lime- 

 stones and volcanics. Here subsidence has been generally accompanied by 

 reef formation. An extended discussion of the coral reef question is given and 

 a modification of Darwin's hypothesis thought to be favored in some measure. 

 The history may be summarized as follows: 



9. Subsidence. 



8. Basaltic intrusions and extrusions. 



7. Uplift and erosion of (6). 



6. Subsidence, with the deposition of about 150 feet of limestones and marls. 



