CONTENTS. 



Page 

 Art. XXIX. — Some Complex Chlorides Containing Gold; 



by H. L. Wells, 315 



Art. XXX. — An American Spirulirostra; by E. W. Berry, 327 



Art. XXXI.— Meteoric Iron from Odessa, Ector Co., Texas; 



by G. P. Merrill, 335 



Art. XXXII. — Some Sharks' Teeth from the California 



Pliocene; by D. S. Jordan, 338 



Art. XXXIII. — An Upper Cambrian Fauna of Pacific Type 



in the European Arctic Region; by O. Holtedahl, .... 343 



Art. XXXIV.— The Great Dustfall of March 19, 1920; by 



A. N. Winchell and E. It. Miller, 349 



Art. XXXV.— Helaletes Redefined; by E. L. Troxell, ... 365 



Art. XXXVI. — Argeocyon, a Probable Old World Migrant; 



by M. R. Thorpe, , 371 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics. — Hydrated Oxalic Acid as an Oxidimetric Standard, A. 

 E. Hill and J. M. Smith: The Atomic Weight of Beryllium (Ghicinum), 

 Honigschmid and Birkenbach, 378. — An Introduction to the Physics 

 and Chemistry of Colloids, E. Hatschek: Distillation Principles and 

 Processes, S. Young, 379. — Separation of Isotopes, F. W. Aston, 380. — 

 Newcomb-Engelmann Populare Astronomie, H. Ludendorff, 381. — The 

 Two Orbit Theory of Radiation, F. H. Bigelow, 382. 



Geology and Mineralogy. — Ueber das Becken, den Schultergiirtel und einige 

 andere Telle der Londoner Archaeopteryx, B. Petronievics, 382. — Die 

 Antike Tierwelt, 0. Keller: Origin and Evolution of th° Human Race, 

 A. Churchward, 383. — The Topographic and Geological Survey of Pennsyl- 

 . vania, G. H. Ashley: Carboniferous Glaciation of South Africa, A. L. du 

 Toft: South Australia Geological Report for 1920, L. K. Ward: Mineral 

 Production in the United States and elsewhere, 384. — The future of the 

 Comstock Lode, 385. — A new Meteoric Iron, G. P. Merrill, 386. 



Miscellaneous Scientific Intelligence. — National Academy of Sciences: A Text- 

 book of Zoology, 386. —Reptiles of the World, R. L. Ditmars, 387.— Mono- 

 graphia delle Cocciniglie italiane, G. Leonardi: Fauna Hawaiiensis, D. 

 Sharp, 388. — World Atlas of Commercial Geology, 389.— The Friendly 

 Arctic, V. Stefansson, 390. — The Evolution of Climates, M. MansoN: An 

 Essay on the Physiology of Mind, F. X. Dercum, 391. — Royal Natural 

 Histoiy Museum at Brussels, 392. 



Obituary. — C. Jordan: B. Moore: A. D. Walker: T. Liebisch, 392. 



