72 PROCEEDINGS OF THE CHICAGO MEETING 



TRVE SPHERE OF PETROLOGY 

 BY CHARLES P. BERKEY 



{Ahstract) 



I'etrographers have been so occupied with the task of asserting and classify- 

 ing and grouping togetlier so many historically quite unlike things that those 

 who naturally follow the leaders in their science have entirely missed its true 

 held, both in its educational and its geological bearings. An attempt will be 

 made to point out what this sphere is. 



Eead from manuscript. 



YOLCAls'OLOOY OF THE HAWAIIAIi ISLANDS 

 BY HENRY S. WASHINGTON 



(Abstract) 



A brief account was given of the general voleanology of the islands. The 

 well known succession from northwest to southeast was pointed out, and the 

 coincidence between this and the same succession in the progress of Pele, the 

 goddess of the volcanoes, according to native legends, was mentioned. After a 

 brief account of the petrology of the islands, the dominance of basaltic, and 

 to a less extent of andesitic, lavas, with the sporadic occurrence of trachytic 

 and other alkalic types, was described ; the paucity of our knowledge of the 

 lavas of most, or all, of the islands was dwelt on, and the need for further 

 collection and study, both in the field and in the laboratory, was urged. 



There would seem to be, so far as one may judge from the present insuffi- 

 cient data, a distinct variation in the chemical composition of the erupted 

 magmas with time, the earlier flows being generally more salic and more 

 alkalic, and the later ones more femic and more calcic. Many more analyses 

 are needed to solve the problems presented. The suggestion was made that 

 possibly beneath the great, recent flows of basalt, as at Mauna Loa and 

 Kilauea, are cores of much more alkalic lavas, possibly trachytic or phonolitic, 

 which represent the earliest phase of volcanicity, such as are seen at Ferru 

 and Arci, in Sardinia, and at other volcanoes. 



The fact that all the inclusions in the lavas throughout the islands are of 

 igneous rocks (gabbros, pyroxenites, Iherzolites, and dunites) and the com- 

 plete absence of inclusions of continental rocks, such as gneisses, schists, 

 quartzites, or limestones, was pointed out and the bearing of this on some 

 problems of the insular botany and zoology, postulating the existence of a 

 former continental mass or connecting bridges, was mentioned. 



Presenteil without manuscript, with lantern-slide illustrations. 



ORIGIN AND COMPOSITION OF CERTAIN OIL SHALES 

 BY REINHARDT THIESSEN ^ 



[Abstract) 



This paper comprises part of a preliminary report on the microscopical 

 study of oil shales. 



' loti-oducecl by E. O. Ilovey. 



