abstracts: mineralogy 149 



Tertiary 



Kenai formation (sands and clays, with lignite beds, and contain- 

 ing fos-il plants) 

 Lower Jurassic 



Tuffs with marine fossils 

 Upper Triassic 



Limestone and tuff with marine fossils 

 Chert 

 Triassic (?) 



Ellipsoidal lavas 

 Paleozoic (?) 



Slates and graywackes 

 Schists 

 Metalliferous deposits occur as veins, stringer lodes, and mineralized 

 felsic (acid) dikes, and these follow two sets of Assuring approximately 

 at right- angles to each other. The ore deposits are chiefly auriferous, 

 but some copper-bearing lodes have been found. The mineralization 

 is probably due to the action of mineral-bearing solutions (magmatic 

 waters) that were forced out of the deeper parts of the igneous magma 

 during its solidification. G. C. M. 



MINERALOGY. — The chemical composition of bornite. Edgar T. 

 Wherry. Science, 42: 570-571. 1915. 

 Discussion of a paper by Rogers (Science 42: 386. 1915.) It is 

 suggested that the variability in the composition of bornite (normally 

 Cu 5 FeS 4 ) is due to the presence of submicroscopic inclusions of one or 

 more of the minerals often occurring as visible inclusions in it, namely 

 chalcocite, chalcopyrite, and pyrite. E. T. W. 



MINERALOGY. — Notes on allophanite,fuchsite, and triphylite. Edgar 

 T. Wherry. Proceedings of the U. S. National Museum, 49: 

 463-467. 1915. 

 A description is given of a specimen of allophanite from Utah. 

 Its index of refraction varies with the water content, being the average 

 of the indices of the constituents, which is regarded as evidence that no 

 complete chemical combination between them exists. Occurrences of 

 fuchsite in Pennsylvania and Colorado are described, and the per- 

 centages of chromium oxide present are given. A new locality for 

 triphylite in New Hampshire is announced and its composition dis- 

 cussed. It contains 60 per cent lithio-ferro-triphylite and 37 per cent 

 lithio-mangano-triphylite. E. T. W. 



