280 TABLE OF CONTENTS. 



Part II. 



THE KOCKS, QUARRIES, AND QUARRY RKGIONS OF THE UNITED STATES. 



Page. 



Steatite. Soapstones ^57 



(1) Coiupo.sitioii and xises of 357 



(2) Soapstones of the various States and Territories 358 



B. Serpentine. Verdantiquo marbles 361 



(1) Composition, origin, and uses 361 



(2) Serpentines of the various States and Territories 362 



C. Gypsum. Alabaster 370 



(1) Composition and uses of 370 



(2) Localities of gypsum in the United States 370 



D. Limestones and dolomites 371 



(1) Chemical composition and origin 371 



(2) Varieties of 371 



(3) Limestones and dolomites. Marbles 374 



(4) Limestones and dolomites. Other than marbles 392 



E. The granites and gneisses 407 



(1) Comi>ositiou and origin 407 



(2) Varieties of granite 408 



(:{) Uses of granite 410 



(4) Granites (and gneisses) of the various States and Territories 411 



F. The pori)hyries. Porphyritic felsites 427 



( 1 ) Composition and origin of the iiorphyries 427 



(2) Varieties of porphyry 427 



(3) Uses of 427 



(4) Porphyries of the various States and Territories 428 



G. Theliparites 429 



(1) Adaptability of Tertiary and jiost-Tertiary rocks to purposes of con- 



struction 429 



(2) Mineral and chemical composition of liparite : 429 



(3) Varieties of liparite 429 



(4) Liparites of the various States and Territories 430 



H. Syenites, trachytes, and phonolites 430 



(1) Definition of syenite 430 



(2) Localities of syenite 430 



(3) Trachytes and phonolites 431 



I. Augite (oustatite hypersthene), plagioclase rocks (trap and greenstone in 



part) 432 



(1) Diabase 432 



(2) Gabbro 4;?7 



(3) Melaphyr 438 



(4) Basalt 438 



K. Amphibole plagioclase rocks (trap and greenstone in part) 439 



(1) Dioriteanddioriteporphyrite 439 



(2) The andesites 440 



L. Schistose or foliated rocks 441 



(1) The gneiss 441 



(2) The schists 441 



M. Fragmeutal rocks 443 



(1) Sandstones, breccias, and conglomerates 443 



(a) Composition iiiid origin 443 



(b) Varieties of 445 



(c) Sandstoues of various Statca and Territories 445 



