CONTENTS 
Page. 
Letter of transmittal 13 
Introduction 15 
Literature on cements 17 
Definition of Portland, natural, and puzzolan cements 18 
Part I. — Materials and Manufacture of Portland Cement. 
Definition of Portland cement 21 
Composition and constitution 23 
Raw materials for Portland cement 25 
Limestones 26 
Origin 26 
Varieties 27 
Chemical composition 27 
Magnesia 27 
Silica, iron, and other impurities 28 
Silica '.'': 29 
Silica with alumina 29 
Iron 29 
Physical characters 29 
Effect of heat 30 
Argillaceous limestone (cement rock) 30 
Cement rock of the Lehigh district 31 
Cement rock in other parts of the United States 32 
Pure hard limestones 32 
Soft limestones ( chalk) 33 
Origin and general character 33 
Geographic and geologic distribution in the 
United States 33 
Composition 34 
Fresh- water marls 34 
Origin of marls 35 
Geographic distribution of marl deposits 35 
Composition 36 
Alkali waste 36 
Blast-furnace slag - 37 
Clays and shales 38 
Slate 38 
Value of deposits of cement materials 39 
Methods and cost of excavating raw materials 41 
Quarrying 41 
Mining 41 
Dredging 42 
Cost of raw materials at mill 42 
3 
