CONTENTS. Vll 



Nmnber 269. 



Page 

 Art. XXI. — Fossil Footprints from the Grand Canyon of 



the Colorado ; by R S. Lull. (With Plates I, II, III) . 337 



XXII. — On the Carboniferous of the Grand Canyon of 



Arizona ; by C. Schuchert 347 



XXIII. — The Cambrian of the Grand Canyon of Arizona ; 



by C. Schuchert 3G2 



XXIV. — The Gravimetric and Volumetric Determination of 

 Fluorine Precipitated as Thorium Fluoride ; by F. A. 

 Gooch and M. Kobatashi . 370 



XXV. — Eruptive Rocks at Cuttingsville, Vermont; by J. W. 



Eggleston 377 



XXVI.— The Formation of Missouri Cherts; by R. S. Dean 411 



SCIENTIFIC INTELLIGENCE. 



Chemistry and Physics — A New Volumetric Method for Silver, L. Schneider: 

 Potassium Iod ate Titrations, G. S. Jamieson: The Chemist's Pocket-Manual, 

 E. K. Meade, 416. — Chemical French, M. L. Dolt, 417. — American Lubri- 

 cants, L. B. Lockhart: Prime Numbers, Sir J. J. Thomson: Polarimetry, 

 second edition, 418. — Theories of Energy, H. Perry, 419. — An Introduction 

 to Science, B. M. Clark: Laboratory Manual, B. M. Clark, 420. 



Geology — Thirty-eighth Annual Report of the Director of the United States 

 Geological Survey, G. O. Smith: Annual Report, 1915, of the Iowa Geo- 

 logical Survey, with accompanying papers, G. F. Kay, 421. — Western 

 Australia Geological Survey, A. G. Maitland : Annual Report of the 

 Director of Mines and Government Geologist for South Australia, 1910, 

 L. K. Ward, 422. — Eleventh Annual Report Geological Survey of New 

 Zealand, P. G. Morgan: Popular Oil Geology, V. Ziegler, 423. 



Miscellaneous Scientific Intelligence — Soil Conditions and Plant Growth, 

 E. J. Rctssell, 423. — Agricultural Bacteriology, H. W. Conn: The Linacre 

 Lecture on the Law of the Heart, E. H. Starling: Index to the Philippine 

 Journal of Science, vols. 1 to 10, 424. 



Obituary — G. A. Lebour: E. A. Letts, 424. 



