CONTENTS 



~ A TEN VOLUME INDEX 



to volumes 41 to 50 will be ready in January 

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Page 



Art. XXYII. — The Nature of Paleozoic Crystal Instability 



in Eastern North America; by C. Schtjcheet 309 ! 



Art. XXVIII. — Notes on the Tertiary Intrusives of the 



Lower Pecos Valley, New Mexico; by D. R. Semmes. . 415 ! 



Art. XXIX. — Entelodonts in the Marsh Collection (con- 

 tinued) ; by E. L. Troxell 431 



Art. XXX. — The Rhyolites of Lipari; by H. S. Washington 446 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics— The Desulphurizing Action of Hydrogen on Coke, 

 A. R. Powell : Chemical French, M. L. Dolt : A History of Chemistry, 

 J. C. Brown, 46o. — The Simple Carbohydrates and the Glucosides, E. F. 

 Armstrong : Chemical Reactions, their Theory and Mechanism, K. G. 

 Falk, 464. — Experiments with Mechanically-played Violins. C. V. Raman: 

 Relativity, A. Einstein, 465. — The Discovery of Electromagnet-ism 

 Made in the Year 1920 by H. C. Oersted, A. Larsen : Augusto Righi : 

 Smithsonian Physical Tables, F. Fowle, 466.-— Logarithmic and Trigo- 

 nometric Tables, E. R. Hedrick. 467. 



Geology and Mineralogy — An Introduction to Palaeontology, A. M. Davis, 467. — 

 Cretaceous and Cenozoic Echinoidea of the Pacific Coast of North 

 America, W. S. W. Kew : T.ype Ammonites, S. S. Buckman : The 

 American Species of Orthophragmina and Lepidocyclina, J. A. Cushman : 

 Geolog}^ of the non-metallic mineral deposits other than silicates, A. W. 

 Grabau, 468.— Text Book of Geology ; Part I, Physical Geology, L. V. 

 Pirsson : United States Geological Survey, Q. O. Smith, 469. — U. S. 

 Bureau of Mines, F. G. Cottrell, 470.— The Production of Platinum in 

 1919, G. F. Kunz and J. M. Hill, 471.— Zeitschrift fur Krystallographie 

 und Mineralogie, P. Groth and E. Kaiser, 472. 



Miscellaneous Scientific Intelligence — The National Academy of Sciences : 

 Publications of Carnegie Institution of Washington: The National Research 

 Council : Recent Publications of the British Museum of Natural History, 

 473— The Nature of Animal Light, 15. N. Harvey, 474. 



Obituary — Sven Leonard Tornquist : M. L. Ducos du Hauron, 474. 



Index, 475. 



