CONTENTS VI T 



Number 17. 



Page 

 Art. XXIX. — Some Complex Chlorides Containing Gold; 



by H. L. \Vells, 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. Jordax, 338 



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



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



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



A. X. Wixchell and E. R. Miller, 349 



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



Art. XXXYI. — Arseocyon, a Probable Old World Migrant; 



by M. R. Thorpe, , 371 



SCIENTIFIC INTELLIGENCE. 



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

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

 Hoxigschmid and Bipkexbach, 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. — 

 Newcoinb-Engelmann Popuiare Astronomic, H. Lttdendorff, 381. — The 

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



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

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

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

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

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

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

 Production in the United States and elsewhere, 381. — 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 Coceiniglie italiane, G. Leonardi: Fauna Hawaiiensis. D. 

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

 Arctic, V. Stefaxsson, 390. — The Evolution of Climates, M. ManSON: An 

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

 History Museum at Brussels, 392. 



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



