CONTENTS. 
PAGE 
Introduction v 
General topography and geology i 
Vulsinian District 3 
Ciminian District 5 
Sabatinian District 5 
Latian District 6 
Hernican District 7 
Auruncan District 7 
Campanian District 8 
Petrography 9 
Introduction 9 
Chemical analyses 10 
Classification n 
Descriptions and names of the rocks 12 
The formal descriptions 15 
Transitional types 17 
Determination of minor constituents 18 
Ischial nordmarkose-phlegrose [augite-trachyte] 19 
Cumal phlegrose [phonolitic trachyte] 22 
Rotaral phlegrose [trachyte obsidian] 27 
Bolsenal vulsinose [vulsinite] 30 
Viterbal vulsinose [leucite-trachyte] 34 
Pallanzanal vulsinose [leucite-trachyte] 40 
Paglial procenose-pulaskose [leucite-trachyte] 41 
Sabatinal beemerose [leucite-phonolite] 46 
Tavolatal janeirose-appianose [leucite-tephrite, tavolatite] 50 
Sorianal harzose [biotite-latite] 54 
Arsal vulsinose-ciminose [vulsinite] 58 
Fiescolal ciminose [ciminite] 62 
Bagnoreal ciminose [leucite-trachyte] 67 
Martinal vicose-ciminose [leucite-tephrite] 71 
Arsal monzonose [vulsinite] 74 
Foglianal ciminose-auruncose [leucite-tephrite] 79 
Teanal ciminose-auruncose [leucite-trachyte] 82 
Orvietal auruncose [leucite-tephrite] 85 
Monfinal shoshonose [biotite-latite] 88 
Foglianal vicose [leucite-tephrite] 91 
Bagnoreal vicose [leucite-tephrite] 96 
Orvietal vicose [leucite-tephrite] 100 
Vesbal braccianose [leucite-tephrite] 103 
Sommal braccianose [leucite-tephrite] 107 
Galeral braccianose [leucitite] 108 
Hernical braccianose [leucitite] in 
Atrial braccianose [leucite-tephrite] 115 
Scalal vesuvose-braccianose [leucite-tephrite] 117 
m 
