280 TABLE OF CONTENTS. 



Part II. 



THE ROCKS, QUARRIES, AND QUARRY REGIONS OF THE UNITED STATES. 



Page. 



Steatite. Soapstones 357 



(1) Composition and uses of 357 



(2) Soapstones of the various States and Territories 358 



B. Serpentine. Verdantique marbles 361 



( 1 ) Composition, origin, and uses 36L 



(2) Serpentines of the various States and Territories 362 



C. Gypsum. Alabaster 370 



(1) Composition and U6es of 370 



(2) Localities of gypsum in the United States 370 



D. Limestones and dolomites 371 



(1) Chemical composition and origin 371 



(2) Varietiesof 371 



(3) Limestones and dolomites. Marbles 374 



(4) Limestones and dolomites. Other than marbles 392 



E. The granites and gneisses . 407 



(1) Composition and origin 407 



(2) Varieties of granite 408 



(3) Uses of granite 410 



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



F. The porphyries. Porphyritic felsites 427 



(1) Composition and origin of the porphyries 427 



(2) Varieties of porphyry 427 



(3) Uses of 427 



(4) Porphyries of the various States and Territories 428 



G. The liparites 429 



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



struction -t 429 



(2) Mineral and chemical composition of liparite 429 



(3) Varietiesof 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 (enstatite hypersthene), plagioclase rocks (trap and greenstone in 



part) 432 



(1) Diabase 432 



(2) Gabbro 437 



(3) Melaphyr 438 



(4) Basalt 438 



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



(1) Diorite and dioriteporphy rite 439 



(2) The andesites 440 



L. Schistose or foliated rocks 441 



(1) The gneiss 441 



(2) The schists 441 



M. Fragmental rocks 443 



(1) Sandstones, breccias, and conglomerates 443 



(a) Composition and origin 443 



(b) Varieties of 445 



(c) Sandstones of various States and Territories 445 



