152 The American Geologist. September, ukjo 
(Chapter II. Normaldiaba.se. 
J. Geological occurrence. 
2. Exterior characters. 
:5. Texture and miueraloRical comi)osition. 
4. Chemical composition. 
Cliapter III. Olivine diabase. 
1. Geological occurrence. 
2. Exterior characters. 
3. Texture and niineralogical composition. 
4. Detailed study of the minerals. 
1). Abnormal pyroxene. 
("liaptcr IV. Plagioclasyte. 
1. Geological occurrence. 
2. Exterior characters. 
H. Mineralogical composition, and order of crystallization. 
4. Detailed study of the primary minerals. 
1). Labradorito. 
a) . Origin of the name, and its use. 
b). Physical characters. 
c). Special crystallographic study, 
d). Optic properties. 
aa). Indices of refraction, and birofringence., 
bb). Optic axial angle. 
cc). Extinction angles. 
e). Chemical composition. 
2). Augite, magnetite and apatite. 
^). Inclusions in labradorite. 
6. Alteration of labradorite. 
7. Alteration of other minerals 
8. Detailed study of the secondary minerals. 
3). Calcite, zoisite and chlorites. 
4). Mesolite and scolecite. 
5). Pseudomesolite. 
6). Magnetite, hematite, limonite and pyrite. 
9. Chemical composition. 
Chapter V. Troctolyte. 
1. Geological occurrence. 
2. Exterior characters. 
3. Texture and mineralogical composition. 
4. Detailed study of the minerals. 
■5, Chemical composition. 
Chapter VI. Orthoclasegabbro. 
1. Geological occurrence. 
2. Exterior characters. 
3. Texture and mineralogical composition. 
4. Detailed study of the minerals. 
1). Labradorite and andesine. 
2). Orthoclase. 
3). Abnormal pyroxene. 
4). Magnetite. 
5). Abnormal apatite. 
6>. Other minerals. 
5. Chemical composition. 
6. Origin. 
