VIII CONTENTS 



Page 



Oil and gas, by T. H. McCulloh - 477 



Oil shale, by William C. Culbertson and Janet K. Pitman 497 



Peat, by Cornelia C. Cameron 505 



Phosphate deposits, by James B. Cathcart and R. A. Gulbrandsen 515 



Pigments and fillers, by C. Ervin Brown 527 



Platinum-group metals, by Norman J Page, Allen L. Clark, George A. Des- 



borough, and Raymond L. Parker 537 



Rare-earth elements, by John W. Adams and Mortimer H. Staatz 547 



Rhenium, by R. U. King 557 



Sand and gravel, by Warren Yeend 561 



Scandium, by John W. Adams 567 



Selenium, by H. W. Lakin and D. F. Davidson 573 



Silica sand, by Keith B. Ketner 577 



Silver, by Allen V. Heyl, W. E. Hall, Albert E. Weissenborn, H. K. Stager, 



W. P. Puffett, and Bruce L. Reed 581 



Sulfur, by Alfred J. Bodenlos 605 



Talc, by C. Ervin Brown 619 



Tellurium, by D. F. Davidson and H. W. Lakin 627 



Thallium, by Keith Robinson 631 



Tin, by C. L. Sainsbui-y and Bruce L. Reed 637 



Titanium, by Harry Klemic, Sherman P. Marsh, and Margaret Cooper 653 



Tungsten, by S. Warren Hobbs and James E. Elliott 667 



Vanadium, by R. P. Fischer 679 



Zeolites in sedimentary rocks, by Richard A. Sheppard 689 



Zinc, by Helmuth Wedow, Jr., Thor H. Kiilsgaard, Allen V. Heyl, and Robert B. 



Hall 697 



Zirconium and hafnium, by Harry Klemic, David Gottfried, Margaret Cooper, 



and Sherman P. Marsh 713 



